Glory Hole - Monticello Dam

A glory hole is used when a dam is at full capacity and water needs to be drained from the resevoir. 

This is the glory hole belonging to monticello dam in california and its the largest in the world, its size enabling it to consume 14 ??400 cubic feet of water every second.

The hole can be seen at the top left of the photo above.

If you were to jump in for some reason your slightly damp body would shoot out near the bottom of the dam .

Kimberley big hole - South Africa 

Apparently the largest ever hand-dug excavation in the world, this 1097 metre deep mine yielded over 3 tonnes of diamonds before being closed in 1914. The amount of earth removed by workers is estimated to total 22.5 million tonnes

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.