Saw this via Instapundit:
Némo33: The Deepest Pool in the World
Europeans, rejoice! At just over 100 feet deep, Belgium's Némo33 may be the world's coolest pool. Filled with heated, drinkable, unchlorinated spring water, the Némo33 is ideal for the leisure diver who wants to practice, improve, or acquire new skills in a safe, warm, accessible area. While the 660,000-gallon pool may be a bit overwhelming for the beginner diver, the year-round temperature of 30°C (86° F), may help soothe their fears. Featuring 3 permanent, underwater bells of airs (a.k.a., "under pressure water caves") so instructors and students can compare notes at depth, 250 anchor points, and 12 portholes allowing visitors to watch divers clear their flooded masks, the facility also features heated changing rooms, a clubhouse, an on-site restaurant, exotic gardens, and rooms for "happenings." Although the website doesn't feature photos of the "happenings" rooms, it does boast some majorly cool shots of the pool, itself.