Kitt Peak National Observatory

Southern Arizona

Dark, clear desert skies are the raison d'être for the Kitt Peak National Observatory, the world's largest collection of optical telescopes. Two radio telescopes and 22 optical telescopes sit atop a spectacular 6875ft-high mountaintop, offering stunning views across southern Arizona. The visitor center has exhibits and a gift shop, but no food. Hour-long tours take you inside the building housing the telescopes (alas, you can't peer through any of them) and the picnic area draws amateur astronomers at night.

For jaw-dropping views of the cosmos, sign up for the Nightly Observing Program, a four-hour stargazing session starting at sunset. It's limited to 46 people ($50; no programs from mid-July to the end of August because of monsoon season). The program books up weeks in advance but you can always check for cancellations when visiting. Dress warmly: it gets cold up here! A light dinner is included, and note that safety concerns preclude children younger than eight.

Kitt Peak is about 1¼ hours west of Tucson, along Hwy 86. There's no public transportation, but Adobe Shuttle runs 12-person vans from Tucson, starting at $275 one-way. It is cheaper to rent a car.