The Boundary Abyss - Tourist Information Portal of the Olomouc Region

The Boundary Abyss

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Teplice nad Bečvou

The Hranice Abyss is a world unique! With a total measured depth of 519.5 metres, the abyss is the deepest abyss in the Czech Republic and at the same time, thanks to its record water depth of 450 metres, the deepest flooded abyss in the world.

The abyss was formed by the collapse of the cave ceiling, which was excavated by aggressive acids in the limestone as they bubbled up from below to the surface. The gaping mouth of the Hranice Abyss drops steeply between the rock walls to a deep pool.

How deep is the abyss?

The dry part of the abyss, from the edge to the surface of the pool, measures 69.5 metres. In 2022, the depth of the flooded area was measured at 450 m. Simply adding up the dry and flooded parts gives a figure of 519.5 m! However, the bottom of the pond itself still remains a mystery - geologists estimate a possible depth of 700 to 1,000 metres.

History and exploration of the abyss

The first written record of the abyss dates back to 1580 and in 1624 Jan Amos Komenský recorded it on a map of Moravia. In 1813, wooden steps were built to the bottom of the dry part of the abyss and it gradually became a popular tourist attraction.

Today, the descent to the lake is no longer possible for safety reasons. The first professional measurement was made in 1902 using a plumb bob. Since the second half of the 20th century, the Hranice Abyss has been explored by diving. A measurement in September 2016, carried out with the help of a robot, measured the depth of the flooded part at 404 metres, making Hranice Abyss the deepest flooded cave in the world. With the 2022 measurement, the depth of the flooded area was moved to 450 m.

Take a peek into the mouth of the abyss!

Visitors usually find it hard to imagine how big a unique feature the abyss actually is, because they only see the above-ground part, which is not very impressive. The biggest "treasure" - the largest part of the abyss is hidden underground. That is why the Hranice Abyss Information Centre was created, so that visitors could learn more about the abyss.

Probably the biggest attraction is virtual reality, thanks to which it is possible to literally look into the abyss. The small cinema shows attractive footage of the dives and also features an interactive 3D model of the abyss, maps and photographs.

The Hranice Abyss Information Centre is located in the station building of the Teplice nad Bečvou train station and is open to the public from April to October.

With the Olomouc Regional Card you can use these services for free.

The unique Hranice Karst

The abyss is part of the Hranice Karst, which lies between the municipalities of Hranice and Teplice nad Bečvou. It is a unique area made up of primordial limestone, whose uniqueness lies in its geological development, where, in addition to normal precipitation, the formation of karst phenomena was also influenced by the outpouring of warm carbonic acid. The most important karst phenomena here are the Zbrašovské aragonite caves and the Hranice abyss.



Tourist information

Do you know

  • The Hranice Abyss is the deepest flooded cave in the world.
  • The Hranice Abyss is part of the Hůrka u Hranic National Nature Reserve - an area at the interface of Devonian limestones and Kulm shales with rare flora and unique karst phenomena. Visitors will be guided through the reserve by a nature trail with several stops.