Nemo 33, named in honour of the mythic sea captain in 20,000 Leagues Under the Sea, is a pool building. Located on Rue de Stalle 333, in the southern part of the Belgian capital, it is the result of eight years of work by the engineer and scuba diver John Beemaerts. Tired of having to go to the dangerous Atlantic to initiate converts into the religion of diving, he conceived of Nemo 33 as a much more pleasant option.

With the help of architect Sebastian Moreno-Vacca, Nemo 33 finally opened in 2004. The 33 refers to the maximum depth of the pool, 33 metres. Or approximately a 10-storey building. For a decade it was the deepest pool on the planet, until the Y-40, in Padua, Italia, broke the record.

Bu what’s it like to enter a building that’s been inundated? What’s it like to go into such a strange space? According to the people who have tried, it’s “a unique experience” with “a sensation of entering a futurist, aseptic fantasy, a disconcerting cross between an underwater operating room and a missile silo that’s been flooded,” the magazine Inmersión wrote. In reality, Nemo 33 is a matryoshka, one building inside another one. The first 12 metres are above the ground line, but the following 21 go below it, as in another Jules Verne novel, Journey to the Centre of the Earth.

And if someone who’s with you has an aversion to water or simply thinks that holidays are not the time for sports, there’s a restaurant and a relaxation area. On the walls there are windows where it’s possible to observe the divers, and the cuisine is Thai. That’s not by chance: this Asian country is a mecca for scuba divers. Just the right tribute for a special kind of immersion.