Nemo 33 by John Beernaerts, 2004
The world’s deepest indoor swimming pool is located in Brussels, Belgium. Its maximum depth is 34.5 meters, 113 feet, and contains 2.5 million liters of non-chlorinated, highly filtered spring water maintained at 30°C/86°F. The pool holds several simulated underwater caves at a 10 meter, 33 feet, depth level. There are also numerous underwater windows installed into several of the pool’s caves in order to allow outside visitors to look into the pool at various depths. The complex was designed by Belgian diving expert John Beernaerts as a multi-purpose diving instruction, recreational, and film production facility.