NR-1 Sinkhole interest, as sinkholes are generally believed to form only in environments which are subaerial, or exposed to the air. In contrast, the NR-1 Sinkhole is believed to be too deep underwater for the area to have been exposed to the air during formation in the Neogene. It was the first documented evidence suggesting that it is possible for karst sinkholes to form entirely underwater. NR-1 Sinkhole The NR-1 Sinkhole is a giant underwater sinkhole located in the Straits of Florida southwest of Key West, Florida. It is found at an approximate depth of of water at the foot of the
Dersios sinkhole Dersios sinkhole The Dersios sinkhole (Greek: Σπηλαιοκαταβόθρα "Ο Δέρσιος" "Spilaiokatavothra "O Dhersios"") is a sinkhole in Arcadia, Greece. The sinkhole, which has a depth of , has been known since antiquity and is located towards the north end of the plateau of Palaiochora at a height of 750 m above sea level on mount Parnon. It is about 45 minutes on unsurfaced road from the nearest town of Tyros in the Kynouria region of Arcadia. The sinkhole was first explored in August 1974 to a depth of by a French team (in collaboration with the Hellenic Speleological Society). Since 2003,