Dersios sinkhole SELAS caving club in Greece has been exploring the cave, doubling the depth and more than tripling the length of the sinkhole. The new discoveries were made in 2003 by cave diving the first sump and emptying it by siphoning the water and in 2005 by emptying sumps in side passages of the 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
Collapse of the World Trade Center both cases, the section of the building that had been damaged by the airplanes failed, which allowed the floors above the impact zone to fall onto the undamaged structure below. As the collapse progressed, dust and debris could be seen shooting out of the windows several floors below the advancing destruction, caused by the sudden rush of air from the upper levels. The first fragments of the outer walls of the collapsed North Tower struck the ground 11 seconds after the collapse started, and parts of the South Tower after 9 seconds. The lower portions of both buildings' cores (60