USS Olympia - C-6
From the moment of her launching in 1892, Olympia was a rare treasure in the U.S. naval fleet, as no sister ships were ever built. She is the world's oldest floating steel warship and the sole surviving naval ship of the Spanish-American War.
Olympia served as Admiral Dewey's flagship at the Battle of Manila Bay, which marked the U.S.'s emergence as a world naval power. Olympia's last official naval mission was to carry the body of the Unknown Soldier from France to the United States in 1921. In addition to being a National Historic Landmark, Olympia is also a National Historic Mechanical Engineering Landmark, on the National Register of Historic Places, and part of the Save America's Treasures program.