#60. North Cascades: Hike Desolation Peak
#57. Isle Royale: Scuba dive shipwrecks
#55. Dry Tortugas: Explore Fort Jefferson
#54. Glacier Bay: Take a boat tour
There are several activities at Glacier Bay, from hiking trails to flightseeing, but taking a boat tour is the most personal way to see all that the park’s 3.3 million acres have to offer. Passengers can see massive ice chunks calve from Margerie Glacier or icebergs exploding to the surface as they break off the base of Johns Hopkins, spotting wildlife from whales and sea lions to grizzly bears and moose along the way
#52. Congaree: Follow the fireflies
A scenic drive through Redwood reveals ancient forests, a rugged coastline, upland prairies, and oak woodlands. When not driving, visitors are encouraged to walk through the Redwood forest for half-day and full-day excursions. At the end of the day, backcountry camping gives visitors the full Redwood experience of sleeping under 240-foot trees.
Mammoth Cave is the most extensive known cave system in the world, at over 400 explored miles, and all the history and beauty can be overwhelming without a guide. From simple tours like the Frozen Niagara Tour to the steep inclines and stairs of the Historic Tour, Mammoth has something for the history or adventure buff inside. Mammoth Cave is open year-round, but tours can vary from season to season.