Grand Canyon
Arizona

If your heart's set on a mule trip down Bright Angel Trail into the canyon, book it now. You may need to reserve a spot as much as a year in advance.

When to go: Summer rim temps are pleasant, 70s and 80s, but on the canyon floor it can be blistering. Go early enough to see the sun rise.
How to get there: Flagstaff, Ariz., is 90 miles from the South Rim.
More to see: Check out the views from the South and West Rim trails, which are mostly paved. The cooler, forested North Rim attracts fewer visitors.

Get more information at www.nps.gov/grca.