Everybody knows the Galápagos, thanks to Charles Darwin. Ever since that upstart English scientist visited in 1835 as a ship's doctor-or at least ever since he described its incredible wildlife in his 1859 book On the Origin of Species-this isolated Pacific archipelago has been famous for its natural wonders. If it hadn't been for their extreme location, 966km (600 miles) off the west coast of Ecuador, mass tourism would have spoiled the islands years ago.

Well, don't speak too soon. Tourism has become Ecuador's fourth-largest industry and the Galápagos its most popular tourist draw by far, with the number of tourists mounting by 12% a year. Immigrant workers have smuggled in goats and pigs that compete with native species for food; invader rats come ashore with cruise ships. The sleepy main town, Puerto Ayora, is rife with trendy hotels and restaurants. Visitors are often a new breed of tourist, zipping around in pick-up trucks madly snapping photos of everything they see. Ecuador's president has declared the islands at risk and may put a cap on the number of visitors (expect prices to rise if that happens). The pristine Galapagos wildlife experience may already be a thing of the past.

What's most remarkable about Galápagos's wildlife is how little they fear humans-and why would they, since they've never had to worry about predators. Young sea lions will show off their best moves as you snorkel among them; mockingbirds will peck at your shoelaces; the blue-footed boobie will perform its famous two-stepped mating dance right under your nose.

An astounding number of unique species thrive on these 19 small volcanic islands (plus about 40 islets); boat travel is essential to view them all. At the Darwin Research Station in Puerto Ayora (tel. 05/526146) on Santa Cruz, the most populated island, visitors can get an up-close view of the gentle giant tortoises that have captured public imagination ever since Darwin first wrote about them. Santiago's rocky tide pools are home to rare fur sea lions and many beautiful heron species; Española has albatrosses and blue-footed boobies; in Fernandina there are vivid marine iguanas and flightless cormorants; Isabela is home to Galápagos's penguins (the world's only tropical penguins); Genovesa has frigate birds and red-footed boobies; and San Cristobal is where California sea lions, red crabs, and lava gulls reside.

Taking a cruise to the Galápagos is a popular option. Departing from Guayaquil, you'll sleep and dine on the cruise boat and take small dinghies to the islands by day for naturalist-led hikes, climbs, kayak trips, or snorkel outings to the best wildlife viewing spots. But choose your tour operator with care, if you want an eco-conscious wildlife visit.

Getting There
With rare exceptions, travelers come by plane to the Galápagos Islands. Tame (tel. 02/2909-900; www.tame.com.ec) and Aerogal (tel. 1-800/2376-425; www.aerogal.com.ec) now offer daily flights to both Baltra Airport, right off Santa Cruz island, and Puerto Baquerizo Moreno, on San Cristóbal island. Note, however, that there are sometimes last-minute changes to flight schedules owing to inclement weather. Always check and double-check with your airline and the cruise company to confirm the airport that will be used for your particular itinerary.

Upon arrival you must pay a $100 fee to the National Park (www.galapagospark.org), which is good for the duration of your stay. This fee must be paid in cash, so be sure to plan ahead and have it ready. Children under 12 pay $50.

Where to Stay
Royal Palm Hotel, Via Baltra Km 18, Isla Santa Cruz (tel. 800/528-6069 in U.S. or 05/5527-409; www.royalpalmhotel.net). Price: Expensive

Finch Bay Hotel, Pinta Estrada, Island Santa Cruz (tel. 05/5526-297; finchbayhotel@spsinter.net). Price: Moderate

Tour Companies
Tour Ecoventura, 6404 Blue Lagoon Dr., Miami (tel. 800/633-7972).

Klein Tours, Av. Eloy Alfaro and Caralina Aldaz, Quito, Ecuador (tel. 888/50-KLEIN in the U.S.; www.kleintours.com).