Natural wonders of america

Kentucky’s Mammoth Cave

In America’s heartland, aptly named Mammoth Cave is the world’s longest cave system. Almost 400 miles of underground passageways have been explored (so far, that is) inside this limestone karst cave labyrinth sculpted by subterranean rivers. See oddly shaped stalactites, stalagmites and other impressive speleothems (cave formations) on a lantern-lit cave tour.

Top tip: Bring a sweater or a jacket, since temperatures inside the cave average 54°F (12°C).

Maine’s Acadia National Park

One tradition in Acadia National Park is for visitors to rise before the sun and drive to the top of Cadillac Mountain for sunrise. Getty Images/iStockphoto

On the wind-blown, tide-splashed Atlantic coast, Acadia is a maritime treasure. Don’t miss hiking Cadillac Mountain (1530ft), the tallest peak on the Atlantic seaboard. On New Year’s Day, you can be the first person in the USA to see the sunrise from its summit. For equally stunning panoramas, show up for golden leaf peeping in autumn.

Top tip: Rent bicycles in Bar Harbor, or bring your own bicycles to explore the park car-free.

Monument Valley

Chances are that those epic landscapes you’ve seen in classic Hollywood Westerns were shot in Monument Valley, where startling sandstone buttes rise up to 1000ft above the sandy desert floor. Today the valley is a Navajo tribal park. For a grand sense of perspective, sign up for a guided horseback tour.

Top tip: The Navajo Nation is on Mountain Standard Time (MST), but unlike neighboring Arizona, it observes Daylight Saving Time (DST).