## Sunday, October 02, 2016 ... /////

### Flooded Czech cave found to be the deepest one in the world

Czechia is a beautiful land, our anthem correctly points out, and there's a lot of cute architecture built on it.

At the same moment, many people feel that the nature is an ultimate prototype of the "average place in the world". It's located in central Europe and the moderate climate zone. After the dissolution of Czechoslovakia, the height of our highest peak has collapsed from 2655 to 1603 meters. We don't have the sea so the lowest-lying area isn't extreme, either. Hřensko (on the Elbe River) near the border with East Germany is the country's lowest-lying village, 115 meters above the sea level – which is funny because visually, Hřensko surely looks like a typical village in the high mountains (and it partially is). You may want to know that Prague is around 200 meters above the sea level in average.

So it looks like you can't find any similar "global extrema" in our homeland. Well, it's completely wrong. Even if someone – or a country – is average from many directions, you may always find directions from which it ends up being extreme. A new example is the Hranice Abyss, the deepest flooded abyss in the world, as a Polish researcher with a Polish-Czech team including a transnational underwater robot (ROV) found a few days ago.

The information about the achievement was described in numerous media, e.g. Google Coverage and National Geographic (which partly funded the dive), Phys.Org, Christian Science Monitor. Polish spelunker Krzysztof Starnawski (see YouTube videos with him) led a team that delved into the cave and found out that it was deeper than the previously believed deepest cave Pozzo del Merro in Italy (near Rome).

The abyss is called the Hranice Abyss ("Hranická propast"; the name "Hranice" denotes a nearby town and means "Border/Boundary/Limit") and is located in Northeastern Czechia (well, also basically Central Moravia, but that is harder to explain to foreigners), about 30 miles both from the Slovak and Polish border, see Google Maps and Mapy.cz. The abyss is located just some 300 meters away from the railway station in Teplice nad Bečvou ("Warmspa Upon the Bleating River", thank me for the translation).

OK, the current proven depth of the water in the cave is 404 meters; the previous Italian record holder had 392 meters (and the bottom has already been reached there). The Czech abyss was previously known to be at least 384 meters deep (since 2014). At the current 404 meters, you should be careful not to drop your USB flash memory over there because they would have to tell you: "Error at 404 meters: file not found". You may also add 69.5 meters of the "dry portion of the cave" to get 473.5 meters in total. Just to be sure, the soil around the top of the abyss is some 300 meters above the sea level, like Pilsen, so the proven bottom may be some 170 meters below the sea level.

However, the main number (404) isn't necessarily the final word. The robot hasn't gotten to the bottom yet – at 404 meters beneath the water level, it was constrained by the length of a cable. (A divers' website had the ingenious idea to bring an extension cord.) Various divers and experts believe that the actual depth of the cave is between 700 and 1200 meters! It's not just a wishful thinking but an estimate based on the high concentration of helium and other gases in the water and other observations.

The infographics posted at the top shows the amazing growth of the estimate of the cave's depth. As recently as in 1961, Mr B. Kopecký showed the depth to be 6 meters. (Well, J.V. Šindel has proven 36 meters of the depth already in 1902, but with a probe.) But since the early 1960s, the estimates were growing at a somewhat accelerating rate up to 260 meters in 2012 which is when the infographics was created. Well, the Poles needed just 4 years to improve the lower bound by 144 meters.

The Hranice Abyss is unique not only because of its depth. Almost all such caves are formed due to rain, i.e. in the top-down way, but this one was formed by bubbles going from the bottom up.

On a video, a Czech guy dives to 170 meters in 2005.

Also, the infographics shows various parts of the cave:

1. Rotunda the Dry One (video)
2. Rotunda the Wet One
3. Monica
4. La Proa
5. The Teethy Witch
6. The Throat
7. The Junior Lake
8. SW Corridor
9. NW Channel
10. New York (video)
11. Lift
Yes, of course, New York is just one of the numerous parts of the cave. I hope that the pompous Yankees at Manhattan will be able to survive the news. (This 2007 picture shows that the branch of the cave really looks like Manhattan on the map.)

If you look at the picture at the top, The Throat (6) at 60 meters is thin but much thicker than the new, so far unnamed, throat 200 meters beneath the water level. It's a bit of a good luck (or something else?) that the super-thin throat at 200 meters ("squeeze passage" found by the Pole in 2014) allows you to go deeper.

The Hranice Abyss, also known as the Godfather Pool, Godfather Pit, Teplice Abyss, or Jackdaw Abyss, may be the deepest one but I think that the Macocha [=Stepmother, up to a changed vowel; a widower with a son married a bitch and this stepmother lured the boy to the sinkhole and helped him to fall down; the son miraculously survived while the stepmother, according to some versions of the legend, jumped down herself] Gorge will remain a much more famous sinkhole and one that attracts many more tourists and daredevils (the jumpers as well as those who perform a handstand above the abyss).

Ivan Mládek has written an on-topic song for almost all blog posts. The song above, Punkva, is about the Punkva River that flows through the Macocha Gorge - which is also mentioned in the song. He sings that he was born there and returns to the caves once in 30 years. Czech readers should also listen to his Love, Betrayal, Macocha.

We have actually lots of impressive caves (the Hranice Area is only about the third most celebrated cave system in CZ, after the Moravian Karst and the Bohemian Karst, to put it easily) and rocks and similar things in Czechia. (Karst is a landscape type with lots of soluble rocks interacting with water which therefore create caves and similar cute things.)

A comparison of the three caves named in this blog post. A dozen of videos about the Hranice Abyss.