The Omni Mount Washington Resort, Carroll

Located within the 800,000-acre White Mountain National Forest, the woods that surround Omni Mount Washington Resort seem largely untouched by the outside world—save for the occasional human that might be zipping through the treetops at 30 miles per hour from the Bretton Woods Adventure Center. The 3-hour Tarzan-esque tour begins in the Base Lodge, where participants are outfitted in harnesses and lead into the forest by experienced guides. From there, guests travel by dual-cable ziplines—nine in total, ranging from 120 to 830 feet long—high above the forest floor as they revel in the beauty of New Hampshire's White Mountain region and learn more about its local geology and cultural history. No two flights are alike since the center is open year-round, and the stunning scenery changes with the seasons: lush greens in the spring and summer, colorful foliage in the fall, and snow-covered branches in the winter.