Longest time spent living in an underwater fixed habitat

Biology professor Bruce Cantrell and biology instructor Jessica Fain (both USA) spent 73 days 2 hours 34 minutes living 7.31 m (24 ft) underwater in Jules’ Undersea Lodge, a steel-and-glass facility anchored at a depth of 9.14 m (30 ft) just off the coast of Key Largo, Florida, USA. They entered the underwater habitat on 3 October 2014 at 12:08 EST and left it on 15 December 2014 at 13:42 EST. During their stay, a joint venture between the Marine Resources Development Foundation (MRDF) and Roane State Community College (RSCC) in Harriman, Tennessee, the scientists hosted a series of weekly videos streamed on YouTube as part of an educational project about marine conservation and biology called Classroom Under the Sea.

The facility is filled with compressed air, preventing water from rising and flooding the area, and is accessed through a small pool that leads to the wet room separating the water from the dry interior. The module also has two private bedrooms and a common room and is monitored 24 hours a day from the land-based "Command Center", which controls the delivery of fresh air, water, power and communications. Bruce Cantrell and Jessica Fain welcomed several guests in the facility, including former astronaut Buzz Aldrin.