Residents of Itäkeskus, a middle-class neighborhood in eastern Helsinki, Finland, descend about 15 meters underground to go swimming, according to a report by newmoney.gr.
The site is not a sophisticated private spa. It is the district's municipal sports center, reached through an entrance behind which stairs and elevators lead down into a large cavity carved out of granite.
Pools, slides and saunas underground
Inside the cavern are swimming pools, diving boards, water slides and saunas. The complex can hold up to 1,000 visitors at a time and attracts about 400,000 people a year, the report said.
Outside, Helsinki can be covered in snow, but underground children play carefree in the pool water, older visitors swim at a relaxed pace, and the saunas operate as they would in any Finnish sports center, according to the report.
Built as a civil defense shelter
The relaxed atmosphere is broken only by the heavy doors separating the different activity areas. Those doors point to the original purpose of the space: in an emergency, the swimming complex can be converted into a civil defense shelter for 3,800 people, the report said.
