Chełm Chalk Tunnels

Starting in the Middle Ages, for hundreds of years, under Chełm's old city buildings enormous pits were dug from residents' cellars.

[1] In the 19th century it was decided to terminate chalk extraction because the tunnels began to endanger inhabitant safety.

The first attempts were made in the interwar period when the tunnels were rediscovered while the municipal water supply system was being built.

The planned route (300 metres long) was destroyed during the Nazi occupation of the city, during which Chełm's tunnels also served as a shelter for the persecuted Jewish population.

After World War II, increased road traffic through the city centre in the 1960s led to many construction disasters.

It runs through three underground complexes of corridors in the Church of Holy Apostles The Messengers, under the Old City Market Square.

[2] While visiting the nearly two km route, which tourists cover in about 50 minutes, one can observe exhibitions of geological, archeological and historical interest.

Even today there are pits being discovered, which make the chalk undergrounds full of riddles, surprises and mysteries.

The chalk undergrounds are thought to measure up to 15 km (9 mi) in length[3][4] — they even reach outside the city border.