Australia: Wilderness Leadership in the Kimberley
Thirty days of trekking from one water hole to the next in Australia's Outback is an education in and of itself--add NOLS expert Leave No Trace instruction and the wisdom of the aboriginal Bardi and you've got yourself some first-class learning. You'll spend your days practicing the fundamentals of expedition camping, traditional hunting techniques, and the essentials of eking out an existence in a hostile environment. Outfitters: National Outdoor Leadership School, 307-332-5300, www.nols.edu When to Go: June, July Price: $3750 Difficulty: Strenuous

Oregon: Native American Sights in Hell's Canyon
Hop in a raft and take on the Class IV Snake River through Hell's Canyon National Recreation area with Jeff van Pelt, master flint knapper and Umatilla tribal historian. You'll stop along the way to learn about Native American petroglyphs, explore pit house sites and rock shelters, and examine some of the thousands of Native American artifacts on the shores of the Snake. At the end of each of the five days, sit back on the bank and contemplate the river crossing where Chief Joseph and his band fled the Wallowa Valley. Outfitters: Hells Canyon Whitewater Co., 541-963-7878, www.hellscanyonwhitewater.com When to Go: August Price: $1000 Difficulty: Easy

Belize: Rainforests, Reefs, and Ruins
Belize sports the world's densest population of jaguars, the Western Hemisphere's largest barrier reef, and the sparsest human population in Central America. Researchers from the American Natural History Museum will guide you on a ten-day adventure through Belize's wild side with visits to Pook's Hill Nature Reserve, Green Hill's Butterfly Farm, and the Maya Medicine Trail, where coatimundi, potoo, and the endangered Morelet's Crocodile make their home. You'll also get a full day to explore Tikal, the massive Mayan ceremonial pyramid in nearby Guatemala. Outfitters: American Museum of Natural History, 800-462-8687 When to Go: March, November Price: $3450, includes airfare from Miami, Dallas, or Houston Difficulty: Easy

South Africa: Monitoring Penguins
Each morning before breakfast on this two-week trip you'll take a stroll down to the beach on Robben Island (where Nelson Mandela was incarcerated for 27 years) to observe Chilly Willy and his pals. Then, after a bite to eat, you'll spend the first part of the day checking nests, observing parent-chick interactions, and weighing African penguins. Dr. Peter Barham from the University of Bristol will brief you on how to avoid being snipped by the defensive birds and explain their behavior and what threatens them. Outfitters: Earthwatch, 800-776-0188, www.earthwatch.org When to Go: March, April, May, June Price: $1895 Difficulty: Easy

Dominica: Restoring Coral Reefs in the Lesser Antilles No, Reef Ball is not the newest fun-in-the-sun watersport, it's a concrete modular reef system used to restore damaged ocean reefs throughout the world. Besides helping to build and deploy reef balls, this seven-night trip includes snorkeling, sea kayaking, opportunities to see some of Dominica's 7 species of whale and 11 dolphins, a guided hike to Boiling Lake, the world's largest volcanic lake, and trips to some of the Caribbean's premier scuba diving destinations. And best of all, you can tell everyone you took a "working vacation." Outfitters: Reef Ball Coalition Inc, 864-879-7543, www.reefballcoalition.com When to Go: February, April, July Price: $1399 Difficulty: Moderate