The SS United States, once the fastest ocean liner, is making its final journey to become the world's largest artificial reef off Florida's Gulf Coast. Tugboats are guiding the vessel to Mobile, Alabama,

After months of multiple delays, the SS United States finally left its longtime home of Philadelphia just before 1 p.m. ET Wednesday. The storied ocean liner’s next stop is Mobile, Alabama, where it will be prepared for its final mission – to become an artificial reef off the coast of the Florida Panhandle.