The Mir Diamond Pipe in eastern Siberia is the biggest man-made hole in the world. the Mir mine produced on average 2 million carats of rough diamonds a year. Below one is photo of world’s largest drain hole which can be made in sea water due to natural effect. This whole is too big that it’s get an frightend. One of the World's Most Biggest hole " DEEP BLUE HOLE in 60 MIL away from BELIZE and it is very amazing…. Its depth is 145m. and 400m. The Blue Hole is the largest ocean sink hole in the world a 1,000 ft in diameter collapsed underground carven. It began life as a fox hole in a remote ravine. But after an eagle-eyed geologist spotted its potential as a diamond mine, it grew and grew... and grew.