Manoa Falls Trail
The rainforest waterfall walk Honolulu grows up on.
You enter through a shipping container, cross a movie-set field, and climb point-eight miles of eucalyptus and bamboo to the falls. Open sunup to sundown every day, and the state charges nothing... the paid lot belongs to neighboring Paradise Park. It's muddy after rain, which up here is often. Don't start after 5:30.