Nemo 33 is an ingenious complex designed by John Beernaerts, located in Brussels, Belgium. It is considered the deepest indoor swimming pool in the world, having a maximum depth of 33 meters and containing approximately 2.5 million liters.
Highly filtered spring water is used to fill up this deep swimming pool. The water is maintained at a constant temperature of 30 °C. The divers find here several simulated underwater caves and outside-visitors have the opportunity to look into the pool at various depths through underwater windows.
Founded in 2004, Nemo 33 was especially conceived for diverse activities such as diving instruction, recreational ventures and even for film production. More about Nemo 33 here.