Mount Rushmore
Keystone, South Dakota
Four big President heads carved into a mountainside: Washington, Jefferson, Lincoln, Teddy Roosevelt. It killed its sculptor, Gutzon Borglum, and had to be completed by his son. Mount Rushmore is not part of the Grand Canyon (although some tourists think it is) and it's a road trip destination that most Americans feel they have to visit, although they may not understand exactly why ("Must... see... big... heads!"). An iconic image that's inspired countless small-scale imitations.
You'd think it had been around forever, but Mount Rushmore is younger than television and Batman.