Officials probe ‘masonic tombs’ in move to uncover their forgotten secrets

The lack of historical documents, its unknown function and inaccessible location have served to reinforce the mysteriousness of the structure. UM Warszawa

Masonic tomb, grotto, dungeon, icehouse, canal, secret tunnel…

These are just some of the names given to one of Warsaw’s most mysterious structures.

City heritage officers have spent this year trying to work out what the underground warren in the Służew district was originally used for. 

The corridor was the site for secret masonic meetings and rituals. Over time, probably because of the catacomb-like niches, it came to be known as the Masonic Tombs.UM Warszawa

But despite a wealth of technical details, it remains a mystery.

The U-shaped, underground brick corridor, which is now home to a protected colony of bats, is dug into Warsaw’s escarpment in the south of the city just behind St Catherine's Church.

According to local stories, a long tunnel is said to lead from it to Czersk Castle around 30 kilometres away.

3D scanning revealed a 60-metre U-shaped corridor, 2 metres wide. Along the entire length of the brick-built tunnel there are 47 arched niches, varying in width from just over a metre to more than two metres. A 6-metre rectangular ventilation duct extends towards the surface.UM Warszawa

In the summer this year, after the bats had woken from their long hibernation, an analysis and inventory of the underground corridor was made by specialists brought in by the city’s heritage protection office.

The measurements were made using 127 three-dimensional laser scans, which provide results with an error of no more than 4 millimetres.

This week, the heritage office released its latest video showing what they found.

Measurements were made using 127 three-dimensional laser scans, which provide results with an error of no more than 4 millimetres.UM Warszawa

The 3D scanning revealed a 60-metre U-shaped corridor, 2 metres wide. Along the entire length of the brick-built tunnel there are 47 arched niches, varying in width from just over a metre to more than two metres. A 6-metre rectangular ventilation duct extends towards the surface.

The investigators believe that it dates back to the time when nearby Wilanów Palace was built by King Jan III Sobieski.

Writing on its website, Warsaw City Hall said: “[T]he corridor was probably built in the second half of the 17th century, parallel to the construction of the palace in Wilanów. Such dating is supported by […] the size of the bricks.”

The underground brick corridor is dug into Warsaw’s escarpment in the south of the city just behind St Catherine's Church.UM Warszawa

During the construction of Wilanów Palace, Augustyn Locci, court architect to John III Sobieski, wrote a letter to the king in which he mentioned a plan to build an icehouse on the northern slope of Służew Hill, where the structure is today.

The location of the icehouse was justified by the proximity of a pond with drinkable water. Lumps of ice could be cut in winter and then stored in the structure.

If the research confirms the 17th-century origin, “it will be a unique Baroque architectural object in Poland,” says Warsaw City Hall.

During the time of Stanisław Kostka Potocki, the underground building was repurposed for a new, mysterious function.UM Warszawa

Later, at the beginning of the 19th century, the area in which the corridor is located became part of a manorial residence called Gucin.

The then owner of Wilanów Palace, Stanisław Kostka Potocki, decided to endow his grandchildren with residences named after them. Natalia received Natolin, Maurycy got Morysin, and August was given Gucin.

In the grounds was a manor house, a building for guests and a gazebo. In the walk garden there were statues and of course the underground grotto.

According to local stories, a long tunnel is said to lead from it to Czersk Castle around 30 kilometres away.CC BY-SA 3.0

When Stanisław Kostka Potocki died in 1821, his wife Aleksandra, to honour her late husband, turned the garden into a grove (gaj) giving the area its current name Gucin Gaj.

During the time of Stanisław Kostka Potocki, the underground building was repurposed for a new, mysterious function.

The corridor was the site for secret masonic meetings and rituals. Over time, probably because of the catacomb-like niches, it came to be known as the Masonic Tombs.

This customary name has survived to the present day, although its use as a tomb has never been confirmed in written sources. As late as 1989, the entry in the register of historical monuments refers to it as ‘Masonic Tombs’.

UM Warszawa

In the latest video Michał Krasucki, the city’s chief heritage protection office, said: “Unfortunately, the end of the corridor has been filled in and is therefore inaccessible. [..] It would have provided valuable information about the original purpose and history of the corridor.UM Warszawa

In the latest video Michał Krasucki, the city’s chief heritage protection office, said: “Unfortunately, the end of the corridor has been filled in and is therefore inaccessible. [..] It would have provided valuable information about the original purpose and history of the corridor.

“Was it another entrance? Or was it walled up with niches and are there human remains there?

“The mysteries of this place are still waiting to be resolved.”

The films in Polish about the scanning of the underground structure are available HERE.