Looking for some deep water so you can practice your diving? Look no further than the Nemo 33 pool in Brussels, Belgium. At 108 feet (33 meters) deep, Nemo is the deepest man-made swimming pool in the world. The entire pool holds an incredible 660,000 gallons (2.5 million liters) of water, and is filled with underwater tunnels and rooms for visitors to explore. Construction took 7 years and cost more than $3 million USD ($3.2 Euros) [source: Swimming World Magazine].
Nemo opened to the public in 2004 and is primarily used by scuba divers and film crews looking to film underwater scenes. Any certified diver can use the pool for about $30 USD (20 Euro), or guests can take classes to learn how to dive safely [source: Nemo 33].