You’d need to take a really big breath or use scuba gear to reach the bottom of a new pool in Poland—the deepest in the world. The training facility, named Deepspot, allows divers to practice plunging a whopping 45 meters (148 feet) underwater. That’s deep enough to submerge a 15-story building!
The walls of Deepspot were designed to withstand the enormous pressure of water pushing against them. “Pressure is what makes your ears hurt when you dive to the bottom of a pool,” says Blake Tullis, an engineer at Utah State University.
Building Deepspot took two years, 2,268 kilograms (5,000 pounds) of concrete, and enough water to fill 27 Olympic-sized swimming pools. It also has a model shipwreck, replicas of ancient ruins, and “caves” for divers to explore.