The SS United States is the largest passenger ship ever produced in the US. It can keep pace with a modern day cruse ships top speed going in reverse.
It still holds records for the fastest crossing of the Atlantic and could reach 50 MPH.
There are currently efforts underway to restore the ship, I really hope they can because I'd take this thing over a crowded jet any day. Go Wikipedia S.S. United States cause if you're on my blog, I know you've got some free time on your hands.