The Y-40 diving pool in Montegrotto Terme, Italy, has a depth of 42 m (137 ft 9.54 in) at its deepest point and contains around 4.3 million litres (945,867 gal; 1,135,939 US gallons) of thermal water. The facility, designed by Emanuele Boaretto and supported by the “Boaretto Group Hotel and Resort”, was officially inaugurated on 5 June 2014 and is used for dive training, leisure diving and scientific research.
The pool is 21 m (68 ft 10.77 in) long and 18 m (59 ft 0.66 in) wide and features various intermediate depths, four caves for underwater diving and a transparent tunnel allowing visitors to walk through the pool at a depth of 5 m (16 ft 4.85 in). The water is maintained at a temperature of 32-34°C (89.6-93.2 °F). The facility had a soft opening on 11 May 2014.