The Macocha Abyss (Czech: Propast Macocha, literally the Stepmother Abyss), also known as the Macocha Gorge, is a sinkhole in the Moravian Karst cave system of the Czech Republic located north of the city of Brno, near the town of Blansko. It is part of the Punkva Caves and the Punkva River flows through it. The sinkhole is about 138.7 meters deep, which makes it the deepest of its kind (light hole type) in Central Europe.
It is a popular tourist attraction for casual visitors to the region, in addition to cavers and advanced technical divers.
According to a popular folk story, the abyss got its name after an evil stepmother who married a widowed farmer from a nearby village. The farmer had a son whom she accepted until she gave birth to her own son. Knowing her child wouldn't inherit anything, she decided to lure her step-son to the abyss and throw him into it. Once she realized what she's done, she decided to end her own life by jumping into the very same abyss. Surprisingly, her step-son survived and was eventually saved by his father and other villagers. Another version of the story says that the step-mother didn't commit suicide but was in fact thrown into the abyss after the villagers learnt what she's done to her step-son.
At the beginning of the Pustý Žleb (Desolate Canyon), below the town of Sloup, the waters of the Sloupský Brook, one of the tributaries of the subterranean river Punkva, helped to form an extensive system of underground passages, domes and abysses, measuring approximately 6,500 meters, known as the Sloupsko-šošůvské jeskyně (Sloup-Šošůvka Caves). At 3,000 meters long the viewing circuit is the longest underground trail open to the public in the Czech Republic.
While the Sloupsko part features large domes and deep abysses, the Šošůvka caves section, on a somewhat smaller scale, is remarkable for its amazing fragile and colorful dripstone formations. One of the stalagmites, called "Svícen" (Candle), has a lace-like collar, an effect created by sinters. Part of the circuit includes the tunnel-like cave known as "Kůlna" (Shed), which has been the subject of much archeological work.