Beneath an ordinary desert town near Kashan lies a second city, dug as deep as a six-storey building is tall. For about 1,500 years, when invaders came, the people of Nushabad did not fight them and did not flee. They went down — through a hole in the kitchen floor or the stable — into a hand-cut world of tunnels and chambers, and disappeared. The attackers would find the houses warm and the lamps still burning, and no one home at all.
Eight kilometres north of Kashan, on the edge of Iran's central desert, sits the small town of Nushabad. Above ground it is unremarkable — a quiet desert town of mudbrick and modern houses. But beneath it lies a second town, entirely hand-dug: a network of tunnels, rooms, and shafts reaching as deep as about 18 metres, built so that the people above could disappear into the earth when they needed to. Locals call it Ouyi (اویی), and it is one of the most remarkable underground refuges in the world.
The reason it exists is simple and grim. This region sat on routes that armies and raiders used for centuries, and the people had no great fortress to hide behind. So they built their defence downward. Beginning, by most accounts, in the Sasanian era some 1,500 years ago, families dug shelters beneath their own homes; over time those shelters were joined into a single connected city, with passages, family chambers, storage rooms, toilets, ventilation, and access to water. When danger came, the population could go underground and live there, sealed and hidden, for days at a time.
The genius of Ouyi is that it was built not for fighting but for vanishing. The entrances were concealed inside ordinary houses — down through an oven, a stable, a well-shaft — so an invader walking the streets would see a normal town and never guess that its entire population was beneath his feet. Inside, the design did the rest: narrow passages that forced intruders into single file, winding U-shaped tunnels with no clear line of sight, concealed pits and rotating trap-stones, and torches that could be lit and snuffed to confuse anyone who did get in. The refuge was used through the Seljuk, Mongol, Safavid, and Qajar centuries — most famously as a hiding place during the Mongol invasion of the 13th century.
The city was largely forgotten until 1983, when a resident digging a well in his house broke through into the tunnels and rediscovered the hidden world below. Much of it has since been cleared and opened, though floods and time have erased many details and the full extent is still not entirely mapped.
The hardest problem with hiding underground is not space — it is staying alive down there. Ouyi solved it with real engineering. Ventilation shafts ran to the surface, carrying enough air for people to breathe even at the deepest levels, around 20 metres down. The chambers were cut to roughly human height so people could stand and move. There was storage for food, access to water (the town's name, "city of cold tasty water," comes from a spring), and toilets — everything a population needed to survive sealed away for days. It was not a panic-hole but a functioning, sustainable shelter, which is exactly what made it work: an enemy could occupy the town above for a week and the people below could simply wait him out.
Ouyi was not built in one campaign. It grew over centuries, dug deeper and wider each time danger came, and was used again and again across the dynasties.
Ouyi is best understood as a machine for disappearing and surviving. Almost every feature served one of two purposes: to hide people, or to defeat anyone who followed them in. Six elements define it.
The way in was concealed within homes — down through an oven, a stable, a well, or a courtyard. An invader in the streets saw a normal town and had no idea a whole population was beneath him. The first line of defence was simply being invisible.
Tunnels were cut just wide enough for one person, often winding and U-shaped, so anyone entering had no line of sight and had to advance uphill in single file — straight into waiting defenders who held the height and the knowledge of the maze.
The design included concealed pits in chamber floors and rotating trap-stones that would tip an unwary intruder, plus dead ends and false turns. The tunnels themselves were a weapon against anyone who did not know them.
Three stacked levels connected by shafts: an upper layer of corridors and entrances, and deeper levels for living and storage during danger. Going deeper meant going safer — and harder for any attacker to reach.
What made long stays possible: ventilation shafts bringing air to the deepest rooms, access to water, storage for food, and toilets. A population could seal itself in and outlast an occupation of the town above.
Each family had its own chamber opening off a main passage — laid out, as one description puts it, like rooms along a hotel hallway. A whole community could live side by side underground, not just survive but wait, in order.
It is worth pausing on how unusual Ouyi's strategy was — because it inverts everything a fortress normally does.
A castle announces itself. It is built high and visible, and its whole logic is to be seen, to look immovable, and to break an attacker against its walls. Ouyi does the reverse. Its entire genius is not being there — a defence based on concealment, not confrontation. The people of Nushabad had no great fortress and no army; what they had was the ground beneath their own kitchens and the patience to dig.
So when raiders came, the town did not resist. It emptied. The population slipped underground, sealed the hidden entrances, and let the attackers take a place with nothing in it. An enemy cannot besiege what he cannot find, cannot starve out people he does not know are there, and gains nothing by burning empty houses. The horsemen would ride on, and the town would quietly refill from below.
This is what makes Ouyi quietly profound. It is the architecture of the powerless — not the grand defiance of a fortress on a crag, but the humbler, cannier survival of ordinary people who could not win a fight and so arranged never to be in one. They beat some of history's most feared armies by the simple, patient act of vanishing.
Ouyi is remarkable, but it is also honestly understood as a site with real gaps in its record — and Untamed Iran would rather say so than smooth it over.
What's well established: that this is a large, multi-level, hand-dug underground refuge beneath Nushabad; that it was used as a shelter from invaders over a long span including the Mongol period; and that it was rediscovered in 1983 by a resident digging a well. The defensive features, the ventilation, and the three levels are all there to see.
What's softer: the precise dating. The Sasanian origin (~1,500 years ago) is the standard attribution, supported by pottery, but the city was dug, redug, and extended over so many centuries that pinning a single "build date" is impossible — and floods and clearance have destroyed much of the stratigraphy that would refine it. Figures for depth (4–18 m, or up to 20 m) and extent vary between sources, and parts of the network remain unexcavated or unmapped. The vivid stories — lamps left burning, attackers unnerved — come from tradition more than documentation.
None of this diminishes the place. Ouyi is genuinely one of the most impressive underground refuges anywhere. It simply means the honest version is "a remarkable ~1,500-year-old refuge, grown over many centuries and still only partly understood" — not a single dated monument with every fact nailed down.
Nushabad sits just north of Kashan, one of Iran's loveliest historic cities, on the edge of the central desert. The underground city is a short visit, and it slots naturally into a Kashan itinerary full of gardens, mansions, and desert.
On the far side of Kashan, the layered mound of Tepe Sialk — one of Iran's oldest settlements, ~7,500 years old at its base. A natural pairing: the deepest time and the deepest refuge of the Kashan area in one trip.
The most famous of Iran's Persian Gardens (a UNESCO group), a Safavid paradise of cypresses, turquoise channels, and pavilions fed by a spring. The lush, open opposite of Ouyi's dark tunnels, a few kilometres away.
The great Qajar merchant mansions — Tabatabaei, Borujerdi, Abbasian — with their wind-towers, sunken courtyards, and stucco. Some of the finest traditional domestic architecture in Iran.
A historic covered bazaar with the beautiful Aminoddoleh courtyard, and the Sultan Amir Ahmad bathhouse with its famous tiled roof — the living heart of a centuries-old oasis trading town.
A drive into the mountains, the famous red-mud village of Abyaneh — ochre houses, ancient dialect, traditional dress — one of Iran's most atmospheric living villages.
Just north, the dunes and salt lake of Maranjab on the edge of the central desert, with a Safavid caravanserai — the classic desert excursion from the Kashan area, close to Nushabad itself.
Two facts of geography explain Ouyi: this was a hot desert town, and it sat on routes that brought trouble. Both pushed life underground.
Nushabad lies on the western edge of the Dasht-e Kavir, Iran's central salt desert, near Kashan. The climate is harsh — fierce summer heat, cold winters, little water — and the cool, stable temperature below ground was itself an attraction: the earth that hid people also sheltered them from the desert's extremes. But the deeper reason for digging was human. This region lay open to the movements of armies and raiders across the plateau, and an undefended desert town had no way to resist them in the open. The town's answer was to use the one asset it had — the diggable earth beneath it — and build its safety downward. The surface setting is ordinary: a quiet town, mudbrick and modern building, desert light, the mountains and dunes not far off. The drama is entirely below, and entirely invisible from the street, which was always the point.
Practically, the underground city stays cool year-round; it is the surface and the journey, not the tunnels, that make spring and autumn the better seasons.
Untamed Iran rates each destination on two dimensions — Adventure, the physical demands a place makes on you, and Legacy, the weight it carries in history, atmosphere, and culture. Ouyi is an easy, short, guided visit — low ceilings and tight passages aside — so its Adventure score is modest. Its Legacy is high: a unique, ingenious refuge that protected a whole population for over a thousand years, and one of the finest underground cities anywhere.
You go down a stairway from an ordinary building, and within a few steps the modern town is gone. The air turns cool and still. The passage narrows until you are walking one at a time, stooping, your shoulders nearly touching both walls, the lamplight throwing your shadow ahead into the dark. Side chambers open off the tunnel — small, low rooms, one after another. Your guide stops at one and says: a family lived in here. For days at a time. With the children. While the riders were in the streets above.
That is the thought that changes the place. This was not built by kings to be admired. It was dug by frightened people, by hand, room by room, over centuries, for one purpose: to keep their families alive when the worst came. Every tight turn was meant to slow a man with a sword. Every air shaft was someone working out how a child could breathe down here for a week. You are standing inside a thousand years of ordinary people refusing to die — not by fighting, but by being impossible to find.
And then you picture it from above, the way the attackers saw it. They smash into the town expecting plunder and prisoners, and find warm hearths, burning lamps, food on the tables — and no one. Not a soul. A whole population gone, as if the earth had swallowed it, which is exactly what had happened, three metres beneath their boots. You came down some steps to see old tunnels. You come back up understanding that the most powerful thing a defenceless people ever did here was simply, completely, to disappear.
A town with no fortress and no army beat some of history's most feared armies by doing the one thing armies cannot fight: it disappeared. Down through the kitchen floor, into a hand-cut world three storeys deep, and gone. The attackers took the houses and found them empty. The earth kept the people.
Nushabad's underground city (Ouyi) is, as the "underground" in its name makes plain, a warren of sealed-off spaces below the earth — where smoking is, of course, not allowed. But the name held one piece of good news for me. Ouyi was the call the townspeople used down there to find one another. And why was that good news? Because it tells you the place is so vast and so tangled that even the people who built it could not easily find each other in it.
So I used that same quality. In one of the rooms — I don't know its name, and of course I could not find it again — I sat down alone and lit my cigarette, and thought about the hardship that had driven the people of this region to take on so much labour and difficulty to lower the risk of being killed by enemies; to pour all their ingenuity, over years of teamwork, into building a refuge like this for an entire town.
I was deep in those thoughts when the sound of someone walking caught my attention. Worried it might be the site staff, cigarette still in hand, I slipped into another room a little further from the sound — just to be safer.
The ideal window for the wider trip. Kashan and the desert edge are mild and bright, perfect for combining Nushabad with the Fin Garden, the houses, and Maranjab. The tunnels themselves are cool whatever the date.
The second sweet spot. Summer heat gone, clear settled weather above ground, comfortable for the whole Kashan circuit. An excellent time to visit.
Cool to cold above ground, and quiet. Fine for the short visit — and the underground city is mild and sheltered regardless. A good low-season option with thinner crowds.
Hot above ground, but the tunnels stay cool — so Nushabad is actually one of the more bearable summer stops in the area. Travel and the surface sights are the limiting factor, not the underground city.
⏰ The underground city is comfortable year-round, so plan around the surface: spring and autumn are best for the wider Kashan trip. The visit is short — combine it with Sialk, Fin, and the old city for a full day, and take a light layer, as the tunnels are cool even in high summer.
The visit itself ends above. What follows is the planning detail — gear, logistics, and questions — tucked away so you can open only what you need.
Nushabad is among the easiest sites in this collection to reach — a short hop from Kashan, on the Tehran–Isfahan corridor. The visit is brief and the underground city stays cool year-round, so planning is mostly about folding it into a Kashan day. Prices move with the rial, so treat figures as orders of magnitude.
Beneath the town of Nushabad, about 8–10 km north of Kashan in central Iran, on the desert's edge. Kashan is a major stop between Tehran and Isfahan on the main road and railway, and Nushabad is a short taxi or drive away. It is a ticketed site with a built entrance, easily folded into a Kashan day.
A large hand-dug underground city — known locally as Ouyi — beneath the desert town of Nushabad, built as a refuge from invaders. Across three levels reaching up to about 18 m deep, it holds tunnels, family chambers, storage, toilets, water access, and ventilation shafts, with entrances hidden inside ordinary houses. People could shelter underground for long periods during attacks.
It is generally attributed to the Sasanian era (224–651 CE), roughly 1,500 years ago, with pottery finds supporting a date around then. It was dug and expanded over many centuries — through the Seljuk, Safavid, and Qajar periods — by the townspeople themselves, who carved out and connected chambers beneath their own homes. Much detail has been lost to floods and time.
Three levels, ranging from about 4 m to 18 m below the surface (some accounts cite refuge as deep as 20 m), connected by vertical shafts and winding passages. The upper level held corridors and entrances; the deeper levels were for living and storage during danger. The layout is deliberately disorienting, with U-shaped, single-file tunnels.
Many: narrow, winding passages that force intruders into single file and uphill toward defenders; concealed pits and rotating trap-stones; ventilation shafts for long stays; water and storage; and multiple hidden entrances inside houses. One account describes defenders lighting torches at the front of a line and snuffing them at the back to confuse pursuers. The whole design favours hiding and ambush over open fighting.
Yes. Accounts describe the people of Nushabad and nearby villages sheltering underground during invasions — most famously the Mongol invasion of the 13th century, and later Timurid and Afghan raids. When attackers entered the town they reportedly found houses warm and lamps lit but the people gone, vanished into the tunnels below.
The visited section is short and lit, and most people walk it comfortably in half an hour or so. But the passages are genuinely narrow and low — cut for a single person, often forcing you to stoop — so it can feel tight, and anyone with serious claustrophobia, back trouble, or limited mobility should expect parts of it to be a squeeze. There are no long crawls on the standard route, and you can turn back at any point.
Nushabad rewards being seen as part of two threads. The first is the Kashan cluster: in a single day you can drop into Ouyi's tunnels, walk the 7,500-year-old layers of Tepe Sialk, wander the Safavid Fin Garden and the Qajar merchant houses, and run out to the Maranjab dunes — one oasis region holding the deepest refuge, the deepest time, and the finest gardens of central Iran. The second is a quieter idea that runs through this collection: the many ways Iranians have survived a dangerous landscape. Set Nushabad beside Babak Castle and you have the two opposite answers to the same threat — the fortress on its crag that survived by being impossible to take, and the hidden city that survived by being impossible to find. One stood and fought; the other vanished into the ground. Both, in the end, were about keeping people alive when the riders came — and both are now places you can walk into and feel exactly how it was done.
Untamed Iran prefers official, scholarly, and first-hand sources, and separates what is established from what is tradition. The design, the dating, the use, and the rediscovery draw on the following:
Facts last reviewed May 2026. Established: Nushabad (Ouyi) is a large, multi-level, hand-dug underground refuge-city beneath the town near Kashan, with tunnels, family chambers, storage, toilets, ventilation shafts, and defensive features (winding single-file passages, concealed pits, trap-stones); it was used as a shelter from invaders over a long span including the 13th-century Mongol invasion, and was rediscovered in 1983 during well-digging. Softer / variable: the precise dating — the Sasanian origin (~1,500 years) is the standard attribution and pottery supports a date around then, but the city was dug and extended over many centuries, and floods plus clearance have erased much stratigraphy; figures for depth (4–18 m, or to ~20 m) and extent vary between sources, and parts remain unmapped. The vivid traditional stories (lamps left burning) come from local memory more than documentation. Confirm opening hours, the guided route, and tickets locally before visiting.