Lowell Observatory
Flagstaff, Arizona
Just one mile off of the then-nonexistent Route 66, Lowell Observatory was built in the 1890s by Percival Lowell, the wealthy son of an elite New England family. Lowell became obsessed with the idea that canals had been dug on Mars -- and with enough money to do whatever he wanted, he had the Observatory built so that he could spend his nights gazing at his favorite planet. Photos from the time always showed Lowell peering into the eyepiece of his big telescope wearing a three-piece suit and a hat.
Nowadays, depending on the weather and availability -- this is still a working observatory -- visitors can view Lowell's hand-drawn "maps" of the Red Planet's canal system, peer through his Mars telescope, or view the heavens through another large telescope he had built at the Observatory to find what he called "Planet X." This telescope was later used, long after Lowell had died, to discover Pluto (His widow tried and failed to have it named "Percival").
Another highlight at the Observatory is Lowell's mausoleum; it's glass-domed, so he can forever be bathed in starlight.