Haleakala Skyline Tour, Maui
The first zipline tour in the United States, the Haleakala Skyline Tour runs through towering eucalyptus trees. The two-hour trip through the canopy takes travelers over five ziplines and across one swinging bridge. Though it's great on a sunny day, consider making the trip when the fog rolls in and hangs on the volcanic slopes. It makes the experience moodier and quiet.