Less than two hours south of Quito, the four-day, roughly 40-mile Volcano Trek from Santa Rita Private Reserve to Cotopaxi National Park plunges you into the heart of Andean volcanoes: Rumiñahui, Pasochoa, Sincholagua, Antisana, and cone-shaped 19,342-foot Cotopaxi. Staying mostly above 12,000 feet, the trail leads to the Inca fortress Pucara del Salitre, across ancient lava flows, and through otherworldly expanses of a wildflower-covered paramo, or grassland plateau. Go independently or with a guide (volcanoland.com), who also offers horseback riding, mountain biking, and cable-assisted ascents into the lush forest canopy.
A two-day mountaineering ascent of snow-capped Cotopaxi is nontechnical, but beginners should hire a guide. surtrek.com
See pink dolphins, crocs, and toucans in an ecosystem supporting 25,000 species of flora on hikes from Napo Wildlife Center Amazon Lodge at Yasuni National Park. surtrek.com.
Trekking in the Central Andes, by Rob Rachowiecki, Greg Caire, and Grant Dixon (Lonely Planet, $18.50 for the book or $5.50 to download the Ecuador chapter)