A vertical drop or shaft is a place in a cave where the caver has to abseil. He needs a rope which is long enough, and so it helps to know the depth of the shaft. Going down the pit means a very long abseil to the bottom. A lot of energy transformed into heat, a problem for rope and abseil equipment. Also it is necessary to climb up the shaft along the rope afterwards using a method called single rope technique (SRT).
We made two different list of shafts, one is about the deepest underground drops, one about daylight shafts. Underground drops are completely underground, both ends, the lower and the upper, are inside a cave. A daylight shafts starts at the surface, which means the daylight shines into the shaft, hence the name. On the other hand there are pitches and single drops. A single drop is a vertical section underground, where you abseil all the way with a single rope. A pitch may be broken, which means it has a ledge or you need a rebelay.
All combinations of above definitons are possible which results in four different kinds of shafts, for each there may be a list of superlatives. We do not have sufficient data for such lists, and unfortunately there is no official institution collecting such data. As a result we have compiled three lists of info available to us. Although we must admitt this is incomplete, we hope it gives an insight into the dimensions of known natural underground spaces.
|Lukina jama||Croatia||516m||The deepest cave of Croatia is 1,392m deep and only 1,078m long. It has a single drop of 516m, making it the cave with the longest vertical drop in the world.|
|Vrtoglavica||Slovenia||603m||This cave, located inside Monte Kanin, has a 603m pitch.|
|Brezno pod Velbom||Slovenia||501m||This cave is 541m deep, but it has a 501m deep shaft, which is blockesd at -377m by a ledge.|
|Höllenhöhle||Austria||450m||Has a 450m deep shaft.|
|Altes Murmeltier||Austria||307m||Has a 480m deep shaft with a ledge and a 307m deep single drop part.|
|El Sótano (de El Barro)||Querétaro state, México||410m||The deepest entrance pit of the world is 410m deep.|
|Sótano de las Golondrinas||San Luis Potosí, México||376m||It is the second deepest entrance drop of the world, 376m deep, and a challenge for any caver.|