Yellowstone National Park

Yellowstone National Park

3 million visitors per year – 3,472 square miles – the largest concentration of geysers and hot springs in the world. Yellowstone National Park, WY.

The center of what is now Yellowstone Park erupted 600,000 years ago, obliterating all life and scattering ash for thousands of miles around. The explosion left behind a 28-by-47 mile crater that contained the world's greatest concentration of geothermal phenomena, including hot springs,, fumaroles, steam vents, mud pots and over 300 geysers. Among the geysers is Steam Boat, which shoots columns of water a record 350 feet high.

Yellowstone is the second largest park in the lower 48 states, encompassing an area larger than the states of Delaware and Rhode Island combined. It is also the oldest park in the country, established in 1872. It has the largest mountain lake (Yellowstone Lake, with 110 miles of shoreline); the biggest elk population in America (100,000 strong); and is the last place in the country where there is a free-ranging herd of bison (4,000 of the woolly beasts).

Peak season tips: This is one of the coldest parks in the continental United States. Be prepared for winter weather at any time of the year. The park receives half its visitors in July and August, overcrowding the roads and limited visitor facilities. The solution: head for the backcountry. Most visitors never venture far from their cars.

Camping: The campgrounds are available on a first-come, first-served basis, except for Bridge Bay, where reservations can be made through Mistix. They often fill early in late summer. Winter camping is available only at Mammoth Campground.

Best one-day trip: From the West entrance, drive along Grand Loop Road to the mile-long Upper Basin Geyser, where boardwalks and trails run among the most outstanding geothermal phenomena in the world. Continue on to Yellowstone Lake.

Water in the park. Yellowstone is one of the few national parks where snowmobiles are permitted. In addition, snow coaches - winter buses on skis - provide a unique way to travel. Photo by Elena.