Bathyscaphe Trieste
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
Georgia (country)
The Krubera Cave is the deepest known cave in the world. It is located in the Arabika Massif of the Gagra Range, in Abkhazia. In 2001, a Russian–Ukrainian team had set the world depth record for a cave at . In 2004, the penetrated depth was increased on each of three expeditions, when a Ukrainian team crossed the mark for the first time in the history of speleology. In October 2005, an unexplored part was found by the CAVEX team, further increasing the known depth of the cave. This expedition confirmed the known depth of the cave at .