Siberia's Kamchatka Peninsula is like Alaska was 50 years ago—only wilder. The region's stretch of the Ring of Fire is three times more active than Alaska's; in total the peninsula has 29 live volcanoes—several of them over 10,000 feet (3,048 meters) tall—plus countless hibernating giants, all lording over a wilderness of geysers and grizzlies and 30-inch (72-centimeter) rainbow trout.

The superlative landscape, open to outsiders for barely a decade, seems to inspire superlative expeditions—including a trip first pulled off by Explorers' Corner in 2003. Its goal: to travel the untamed Zhupanova River from source to sea. "Source," in this case, means the snows of the 5,100-foot (1,554-meter) Semyachik volcano, reached by a double-rotor Mi-8 helicopter. "Sea" is the Bering Sea, located just 20 miles (32 kilometers) of hiking and 110 miles (177 kilometers) of easy kayaking away. "You're paddling down a subarctic river with erupting volcanoes on both sides," says guide Olaf Malver. "There are hot springs, and on the first trip we had ash pile up on our tents one night." The river is shared with huge runs of arctic char and silver salmon—plus the occasional bear swimming just in front of you. $5,100 for 15 days; 510-559-8099; www.explorerscorner.com.

Twenty-four other new trips made the cut to be included as one of 2005's best outfitter excursions. Read about each one of them in the November issue.

From the print edition, November 2004