There were two Mary Blair murals in California Tomorrowland... Legend says that the one pictured here still exists (at least partially), covered up in the late 90s by a more contemporary-looking facade.

The other, sadly, was destroyed to make way for "Star Tours" in 1986. It really surprises me that nobody thought the murals were worth preserving elsewhere.
D: DESTROYED??? Good lord, people, preservation is not impossible. So much gets lost so quickly.