How low can you go? When the world's deepest pool opens in Poland later this year, complete with underwater caves and overhangs, you'll be able to go as low as 45 meters (148 feet).

An ideal training spot for professional scuba divers, the Deepspot pool will hold 8,000 cubic meters of water - 27 times the volume of an average 25 meter pool.

The pool is currently under construction in the town of Mszczonow, less than 30 miles from Warsaw. About 1,100 tonnes of steel are being used to reinforce its structure which includes a simulated "blue hole" plunging down to its deepest point.

Designers say it will suit both beginners and more experienced divers, but those who don't want to get wet can also enjoy the facilities, thanks to an underwater tunnel for spectators.

Surrounding conference and training suites will also look out onto the pool's interior, as will hotel" rooms with a view."

Once it opens, Deepspot will knock the Italian Y-40 Deep Joy off the top spot. Located in the Montegrotto Terme resort area, near Venice, the pool there is the star attraction of the Hotel Millepini.

Yet if all goes to plan, Deepspot will not hang on to the accolade for long as an even deeper pool is expected to open in Britain in 2020. Currently being built in Colchester, the Blue Abyss will be 50 metres deep.

John Vickers, managing director of Blue Abyss, says his project is "more than just a super-sized pool", and will operate as a "commercial astronaut training centre.... and a human performance centre helping people reach the peak of their physical capabilities."