This pool is called, Y-40 Deep Joy and is in Italy. It is 40 meters deep (135 feet). It is located by Hotel Millepini in Montegrotto Terme. The pool has a wide 21-meter (68-feet) by 18-meter (59-feet) surface and at first sight appears just like any other ordinary pool. However, as the swimmer goes beyond 15-meters (49-feet), it becomes a narrow tub that goes straight down 28-meters (91-feet).
Most people who go to pool are just people who wanna swim, but some are divers wanting to practice and extreme divers, who want to practice. There are also aqua tubes that divers can navigate for fun or for practice. It is alway relatively warm down there due to thermal heaters installed so it is always war no matter how far down you are.