The historic SS United States sank off Destin, Florida, becoming the world’s largest artificial reef in the Gulf of Mexico at 180 feet. Launched in 1952 as the fastest ocean liner, the vessel served for 17 years before retiring in 1969.

Following decades docked in Philadelphia, soaring daily fees of $1700 overwhelmed the non-profit conservancy, finally forcing an end to preservation efforts and starting its new underwater marine habitat role.