It was once a bomb shelter. But on early winter mornings, 10-Z Bunker is where you go to find refuge from the cold, and a room for the night. 10-Z, after all, may have once been a refuge from the threat of nuclear war, but today, it serves as a bed and breakfast. Albeit a very cold one.

It is just one of the many subterranean delights found in Brno, a city in Czech Republic. It’s a fascinating city above the ground, replete with dark bars, good beer, modernist buildings and much history. Dig deeper, or just go underground, to find more treasure and history. There’s the Capuchin Crypt with skeletons of the monks of the order, some still clutching their rosaries and crucifixes; their bodies preserved by the dry air.

The 10-Z Bunker gives a glimpse of what life could’ve been, while over in the main square, the Labyrinth underneath Zelný trh (Vegetable Market) showcases what life was like.

In the early 13th century, the cellars under the Horní trh (Upper Market) were used for storage of food, wine, and beer—think of them as old-school refrigerators. They were built under people’s homes at the time, and functioned as shelters during wartime. A guided tour here shows an alchemist’s lab where doctors and physicians once practised, and a wine cellar and tavern harking back to the local tradition of winemaking. Perhaps the most chilling is the section showing the punishments for dishonest people —there are replicas of torture devices and a cage of fools (a small iron cage where people couldn’t sit or stand).

Špilberk Castle is the city’s biggest landmark, and has much to see above and below the ground. It is under the hill on which the castle stands that Germans built 10-Z Bunker during WWII, as a civil defence shelter from American and Soviet bombardment of Brno. It served as a wine store after the war before being confiscated by the Communists, and ultimately opening to public in 2016 as a retro hotel. Under the castle, you can find the casemates, which resound with the untold stories of political prisoners. Back in the 1700s, these prisons were once considered one of the harshest in Europe, and were in use during the Nazi occupation of Czechoslovakia. Today, there are dummies showcasing living conditions.

At the entrance of 10-Z, visitors are greeted by a row of thick Army field jackets, which help deal with the temperature in this bunker (a few degrees colder than outside). A labyrinth of dark tunnels, decorated with rows of Army hats, medicine boxes, gas masks, an old Army motorbike, telephones, typewriters, and old sinks, lead to different rooms. There is a diesel generator engine room, air filtration room, battery room, an emergency telephone exchange and a decontamination room that form the technical part of the shelter. Tiny televisions screen short videos and documentaries of the people who built and took shelter in the bunker during WWII. There’s even a ‘cell of death’ door, taken from a Brno prison, which has carvings of prisoners who were sentenced to death during WWII.