The 1½-mi-long chasm opened to the public in 1870, becoming the country's first natural tourist attraction. The geological spectacle continues to be popular and is often overrun with visitors in summer.
A deck allows you to view formations such as Elephant Head with its trunk of rock. The trail around the rim provides soaring views, and stone walkways and stairways descend into the chasm. Sightseeing can be combined with a kayak, raft, or inner-tube ride on the
Ausable River. Two-hour lantern tours ($20 per person) start at dusk. The flickering lights transform the 500-million-year-old mass of time-sculpted stone formations. Reservations are required.