Bering Land Bridge National Preserve

This remote preserve on Alaska's Seward Peninsula protects a remnant of the Bering Land Bridge, the thousand-mile-wide grassland that connected Asia and North America during the Ice Age and carried the first people into the Americas. Trail Creek Caves held some of the earliest evidence of people in the Americas.

There are no roads or facilities; access is by bush plane, boat, snowmobile, or dog sled, and visitors can soak in Serpentine Hot Springs. For a challenge, charter a flight to explore the preserve's lava flows and caves deep in the backcountry.