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.
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
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.
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.