La Tour Percee

The longest natural erosion arch in the Alps (at 32 metres, and a double one at that) was only discovered in 2005, in the Chartreuse mountain chain above Grenoble, at the southern tip of the Jura mountains (part of the Pre-Alps), long famed for the bittersweet herby alcohol produced by the Carthusian monks (reputedly some of the most austere, meditating in their isolated eyrie, where they have been based since 1084). The find was made by a hiker who was researching a book on the hidden unknown treasures of the range, later published as Chartreuse inédite : Itinéraires insolites.

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Crveno Jerezo

Can you believe that the sinkhole you see in this picture is a 522m deep? The cliffs have a height of 241m and the intensely blue lake is about 280m deep. In 1942 one of the cliff walls collapsed after an earthquake. No place to have a swim! (The water is also very cold at 10 °C)

Crveno Jezero (Croatian for Red Lake due to its red cliffs) is the third deepest sinkhole on the planet. You actually cannot even see the immenseness of this sinkhole in a photo. Standing at the edge will make you feel incredibly small and a bit dizzy.

What is even scarier is that at the bottom of the sinkhole the cave extends down even further. Speleologists have not yet been able to determine how deep it goes down due to a very powerful undercurrent in the lake at about 170m depth, which leads scientists to believe that the sinkhole is connected to other watersystems. The presence of a rare species of fish in the sinkhole further fuels this hypothesis. The species: delminichthys adspersus, can occasionally be seen in surrounding rivers and springs in dry seasons suggesting that the sinkhole is connected to the spring and rivers. Delminichthys adspersus are only found in the Dinaric Alps.

The Dinaric Alps are known for its many its karstic formations, the upper Creteceous limestone has formed over 20 large holes that were formed by underground rivers. Due to its near vertical walls, Red Lake is believed to be the youngest of this group. Nearby Modro Jerezo (Blue Lake) is a little bit less deep at 220 m. The earthquake of 1942 caused a landfall and reduced the depth of the lake considerably.

One last scary fact, can you believe that people actually basejump into this gaping hole? Watch a video here (in Croatian):https://www.youtube.com/watch?v=cZIm0BVZ0qI


Image: Copyright Barbara Oosterwijk. Crveno Jerezo as seen from above.

See here for a cross-section of the sinkhole:http://www.wondermondo.com/


Hoher Dachstein is a strongly karstic Austrian mountain, and the second highest mountain in the Northern Limestone Alps.

The geology of the Dachstein massif is dominated by the so-called Dachstein-Kalk (“Dachstein limestone”), dating from Triassic times. In common with other karstic areas, the Dachstein is permeated by a rich cave system, including some of the largest caves in Austria, such as the Mammuthhöhle and the Hirlatzhöhle.

Up on nearly 3000 meters you feel very small looking down, even though it’s far from the highest mountain in Austria. An amazing place to visit! More photos from our trip here is to come