Restoration works in the gardens of the Royal Castle in Warsaw led to a discovery of a 19th-cent. tunnel leading towards the Vistula river. Existence of tunnels under the river is one of the most well-known urban legends in Warsaw.
The tunnel was discovered in October 2017. The structure is said to be running across the gardens toward the Vistula river. Archaeologists working at the site used a mechanical digger to uncover the entrance to the structure covered by large stone slabs. The tunnel is accessible by a shaft that was uncovered while digging for a future fountain reservoir. The researchers date the structure to the 19th century and state that its length is known at a distance of around 100 metres. It is also believed that the structure might have been used as a sewage disposal leading from the royal kitchens.
The tunnel is around 1.5 metres high and consists of bricks and wooden elements forming an arch. It runs from the Grodzka street for several metres, where it drops by 3 metres. Similar entrance shafts as the one that was uncovered were discovered every 10 metres. They allowed for easy access of the tunnel. The underground passage ends by Wisłostrada – one of the main arteries running along the Vistula’s West bank. According to Maria Szczypek from the Royal Castle, the arch is made of bricks and wooden logs were used at its base so that water would not wash away the subsoil, and represents a typical sewage canal from the 19th century.
The walls of the tunnel are covered in stalactites and fungus. The structure is going to be preserved but needs securing. The authorities of the Royal Castle plan to allow sightseeing of the tunnel in the future, but the law prohibits visiting structures located at this depth, and the canal is 40 centimetres too short by safety standards. the idea, as stated, awaits more expert opinions and probably building some additional infrastructure. At this point the fate of this potential tourist attraction is uncertain.
(after Zamek Królewski & TVN Warszawa)