If you like to showcase your superior diving skills you may want to check out Italy's Y-40 Deep Joy. As the name indicates, the depth of this newly opened pool extends down 40 meters (131-feet) - the height of a 12-story building or nine double-decker buses stacked atop each other!

The pool that is located at the Hotel Millepini in Montegrotto Terme, 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 narrows into a circular well-like hole that plummets down a steep 28-meters (91-feet). As you may have guessed, the Y-40 is not for casual hotel guests seeking to cool off with a quick dip, but for scuba enthusiasts and free-divers looking to perfect their skills before going into the open seas. At the pool's bottom lie some underwater caves that enable athletes to practice their sub-aquatic landscape negotiating prowess.

What makes the pool even more unique is that it is filled with 4,300 cubic feet of thermal water from the nearby local springs that the area is well-known for. This means that despite its depth, the water is always a comfortable 32°C (89°F) to 34°Ç (93°F) alleviating the need for cumbersome wetsuits. A sunbathing platform on the deck, allows divers to take a breather following their scary plummets.

While the hotel does provide special scuba as well as free-diving lessons for novices brave enough to want to take the plunge, they realize that most people are just content to watch the experts. Hence, they have added a suspended transparent viewing tunnel where visitors can stand and gasp in awe, at those crazy enough to leap to the bottom.

For those fortunate enough to be present at the inauguration ceremony, it meant watching Italian world free-diving champions Umberto Pelizzari and Ilaria Molinari (who dressed as a mermaid), showing off their amazing skills! The officials at Millepini hope that Y-40 will transform Montegrotto Terme into a major international diving center. Given that it makes the world's previous deepest pool, the 34.5-meter (113-feet) Nemo 33 in Belgium appear almost shallow, they are likely to succeed in their mission!

While the world's deepest pool may be just for the brave, the world's biggest one is fun for all. Located at the Alfonso del Mar Resort in Algarroba,Chile the half-mile long stretch of water that covers 20-acres and holds more than 66 million gallons, is the size of 6,000 standard size pools put together! It is so big that most guests don't even bother trying to swim across - They just use kayaks or small boats to get from one end to the other.

Resources: innovation.msn.uk, metro.co.uk, cnn.com