16.The USNS Comfort, by comparison, is huge. It's almost 900 feet long, which is longer than the length of two football fields.
17.Normally, the Comfort and the Mercysit dockside and are only manned for basic maintenance.
18.They are a part of the US Navy, but are actually classified as "auxiliaries."
19.Both the Mercy and the Comfort were originally large oil tankers.
20.More recently, they've been known to go out on humanitarian missions to other countries.
21.And these international humanitarian efforts can even include veterinarian care!
22.Before the Mercy and the Comfort, the US Navy had a number of other smaller medical ships (no longer operational) that served in World War II, the Korean War, and the Vietnam War.
23.And finally, believe it or not, medical ships have been around for more than 200 years — some of the earliest hospital ships were actually converted paddlewheel steamboats used during the Civil War.