Neutral Buoyancy Laboratory - world's largest indoor astronaut training pool

The Neutral Buoyancy Laboratory at NASA's Johnson Space Center contains a 6.2 million-gallon pool used to train astronauts for extravehicular activity and is described as the world's largest indoor pool for astronaut training. The pool measures roughly 202 feet long, 102 feet wide, and 40 feet deep and houses full-scale mock-ups of International Space Station modules for practice. NASA operates the facility to simulate microgravity using neutral buoyancy techniques.