Hidden Prague: Underground, Alchemy and Secrets

Every visitor to Prague sees the Astronomical Clock and Charles Bridge. This tour shows you what most of them miss — the hidden layer of the city that lies behind unmarked doors, beneath street level and inside churches that most people walk straight past.

In ninety minutes, your private guide will take you through the narrow lanes of the Old Town to three places you are unlikely to find on your own: a medieval underground beneath one of Prague's oldest buildings, a Renaissance alchemy laboratory with a hidden entrance, and a church where a real severed arm has been hanging from a chain for over 400 years.

No ghosts. No costumes. No theatre. Just the real hidden Prague — and the true stories behind it. Led by a licensed guide with 17 years of experience and over 10,000 happy guests.

The Powder Tower and the lanes of Old Town

The tour begins at the Powder Tower — one of the original 13 city gates of medieval Prague, built in 1475. From here your guide leads you into the narrow lanes of the Old Town, where the street layout has barely changed since the Middle Ages. Between the tourist crowds and the souvenir shops, there are hidden courtyards, forgotten passageways and stories written into every façade — if you know where to look.

Medieval underground

Your first stop takes you below street level — into medieval stone cellars beneath one of the oldest buildings in the Old Town. In the 13th century, the city raised its entire street level by several metres to protect against Vltava flooding — burying what had been the ground floor beneath the new city. These vaulted chambers have been here for centuries, hidden beneath the streets of the Old Town.

The church with a severed arm

Next, your guide takes you to one of Prague's most beautiful Baroque churches — over 20 decorated altars, a history stretching back to the 13th century, and an interior that takes your breath away. But the reason we are here hangs near the entrance: a mummified human forearm, blackened and shrivelled, suspended from a chain.

The story goes that a thief hid inside the church overnight and tried to steal from the statue of the Madonna on the main altar. The statue, according to legend, seized his arm and would not let go. When parishioners arrived the next morning, they could not free him. So they cut off his arm. It has been hanging here ever since — a warning that has lasted over 400 years.

A secret alchemy laboratory

The final stop is the most extraordinary. Hidden beneath one of the oldest buildings in Prague's Old Town, a Renaissance-era alchemy laboratory lay sealed and forgotten for centuries — until severe flooding in 2002 opened a hole in the street above and revealed what was underneath.

Inside, you enter the alchemist's study — elixir bottles, manuscripts, strange instruments. Then comes the moment no one expects. Your guide opens a hidden door. A narrow spiral staircase leads down to the underground laboratory: a furnace, ventilation shafts, a glass-blowing chamber and tunnels that reportedly once connected to Prague Castle itself. This was where alchemists in the court of Emperor Rudolf II searched for the Philosopher's Stone and the Elixir of Eternal Youth — an art that was both celebrated and forbidden.