(CNN) — Yes it's a dive hotel, but not that kind of dive hotel.

An Italian spa complex has just opened a swimming pool certified by the Guinness Book of Records as the world's deepest. Named the Y-40 Deep Joy, the pool is now the star attraction at the Hotel Millepini, located in the Montegrotto Terme resort area, near Venice, Italy

This isn't the kind of facility aimed at jaded business travelers hoping to cram in a few laps before they head upstairs to order room service.

Deep Joy features a shaft that plunges down ... and down ... and down until it hits a depth of 42 meters (138 feet), a space that could easily accommodate a 13-story building.

Designed by architect Emanuele Boaretto and a year in the making, Deep Joy is expected to attract scuba enthusiasts and freedivers -- aquatic athletes whose incredible lung control allows them to spend minutes at depth on a single breath.

Thermal springs

The pool is filled with 4.3 million liters (1.1 million gallons) of thermal water from local springs, allowing divers to plunge without the skin suits they'd need in open seas or lakes.

It also contains underwater caves aimed at training scuba divers to negotiate sub-aquatic landscapes. There's also a suspended transparent viewing tunnel that allows spectators to watch the divers in action.

Deep Joy was inaugurated earlier this year at a ceremony in which Italian world freediving champions Umberto Pelizzari and Ilaria Molinari (who dressed like a mermaid for the occasion) plumbed its depths.

The pool's creators hope it will transform Montegrotto Terme into an international diving center and raise the profile of what is said to be Europe's largest area of thermal springs.

It'll also be open to beginners who want to experience its depths under supervision. Just don't drop your locker key.