Deep attraction — The Y-40 Deep Joy, the world's deepest swimming pool, sinks to a depth of 42 meters. Courtesy Boaretto Group Hotel & Resort Subaquatic spectacle — At the Hotel Millepini Terme in Montegrotto Terme, Italy, the pool features an underwater viewing tunnel. Courtesy Boaretto Group Hotel & Resort Water down — The pool is aimed at scuba enthusiasts and freedivers capable of holding their breath for minutes at a time. Courtesy Boaretto Group Hotel & Resort Diving champion — Italian freediving champion Umberto Pelizzari attended the pool's opening. Courtesy Boaretto Group Hotel & Resort Mermaid marvel — Illaria Moliari, another Italian freediving champ, dressed as a mermaid to mark the pool's inauguration. Courtesy Boaretto Group Hotel & Resort Warm waters — Deep Joy contains 4.3 million liters of water heated to 32-34 C by thermal springs. Courtesy Boaretto Group Hotel & Resort Water world — The pool also features caves to simulate sea floor environments. Courtesy Boaretto Group Hotel & Resort Prev Next