Park offers lots to do above and below ground

Each year, Mammoth Cave National Park offers hands-on, accessible and free activities tailored to every age, but only about a half-million people come to enjoy them. (By comparison, nearly 5 million visit the Grand Canyon.) And though it’s famous for its 365 miles of caverns and passageways — the longest cave system in the world — Mammoth has much more to offer. Families can hike, bike and ride horses through lush old-growth forest and canoe and fish along 30 miles of rivers.

Inside the cave itself, eerie limestone formations with names like "cave bacon" drape next to drooping stalactites and jutting stalagmites. Enormous cave "rooms," some so large they were used as banquet halls in the early 1900s, lead deep underground, where local American Indian tribes mined for gypsum thousands of years ago.

Whether families are looking for subterranean secrets or forest beauty, this park has all the makings for a vacation of mammoth fun.

Visitors of all ages can explore a world underground at Mammoth Cave National Park.