Bingham canyon mine, utah

Bingham canyon mine, utah , this is supposedly the largest man-made excavation on earth. extraction began in 1863 and still continues today, the pit increasing in size constantly. in its current state the hole is 3/4 mile deep and 2.5 miles wide. Great blue hole, Belize situated 60 miles off the mainland of belize is this incredible ??geographical phenomenon ?? known as a blue hole. there are numerous blue holes around the world but none as stunning as this one. At surface level the near perfectly circular hole is 1/4 mile wide, the depth in the middle reaching 145 metres. obviously the hole is a huge hit with divers.