This was part of one of those emails that everyone sends around, but I thought it worth sharing because of the wonderful, intriguing photos. And truth be told, I'd never heard of some of these phenomena. Enjoy!
1. Kimberley Big Hole, South Africa
Apparently the largest hand-dug excavation in the world, this 1,097-meter- deep mine yielded over three tons of diamonds before being closed in 1914.
2. Glory Hole - Monticello Dam, California
This is the "glory hole" at Monticello dam, and it is the largest spillway of its kind in the world, its size enabling it to consume 14,400 cubic feet of water every second.
3. Bingham Canyon Mine, Utah
This is supposedly the largest man-made excavation on earth. Extraction began in 1863 and continues today, the pit constantly increasing in size. In its current state the hole is miles deep and 2.5 miles wide.
4. Great Blue Hole, Belize
This incredible geographical phenomenon known as a blue hole is situated 60 miles off the mainland of Belize. There are numerous blue holes around the world, but none as stunning as this one.
5. Mirny Diamond Mine, Serbia
This holds the title of largest open diamond mine in the world. At 525 meters deep, with a top diameter of 1200 meters, there's even a no-fly zone above the hole due to a few helicopters having been sucked in.
6. Diavik Mine, Canada
The mine is so huge and the area so remote that it has its own airport with a runway large enough to accommodate a Boeing 737. It is equally impressive when the surrounding water is frozen.
7. Sinkhole in Guatemala
These photos are of a sinkhole that instantaneously appeared when the soil beneath was eroded as a result of a broken water main early this year (2008) in Guatemala . The hole swallowed a dozen homes and killed at least 3 people.