USS Monitor (ironclad)
From Memory Alpha, the free Star Trek reference.
The USS Monitor was a 19th century steamship employed by the United States of America during the American Civil War, which was outfitted with iron plating and a rotating turret with two large cannon.
The Monitor later took part in the historic Battle of Hampton Roads, the first battle between ironclad vessels, when it stood off against the Confederate's own ironclad CSS Virgina.
A painting depicting this battle was stored in the USS Enterprise's library computer in 2254, and was among the materials viewed by the Talosians when they scanned the Enterprise computer. (TOS: "The Cage")
[edit] Background
The Monitor was later referenced by Abraham Lincoln in what was a deleted scene from "The Savage Curtain". In this scene, Lincoln, who was amazed at the wonders of the Enterprise stated, "We thought our Monitor the most formidable vessel imaginable. An iron ship that floated on water! You can imagine my amazement at an iron ship that floats on air..." [1]
