At 19,393 feet, Cotopaxi is said to be the second highest active volcano in the world. It is the centerpiece of Cotopaxi National Park, about 50 miles southeast of Quito. Along the way, one gets to travel on the Pan American Highway (which is more like a secondary road than a highway) as it winds through small towns and villages. The scenery along the way is quite beautiful.
Once inside the park, it is possible to drive up the volcano to about 14,500 feet. Along the way, you will pass through a dense forest, populated with some domesticated llamas, and eventually rise above the tree line into the paramos, or high moors. Lake Limpio Pungo (which means "clean heart" in a combination of Spanish and Quechua, the local Indian language) supports a flock of birds as well as serving as the watering hole for wild horses and other animals. The area has a vast, stark beauty. Unfortunately, I never was able to see the entire volcano all at once because of clouds, but from the portions I could see I could tell it was a spectacular sight.
Major eruptions of Cotopaxi took place in 1744, 1768, and 1877. It's last significant eruption was in 1904. Cotopaxi is part of the magnificent "Avenue of the Volcanoes", a string of active and inactive volcanoes that punctuates the Andes Mountains' north-south traverse of Ecuador. Later, on a flight from Quito to the rain forest, I had a clear view of the volcanoes from the air. The Satellite Photos page shows an aerial view of the Avenue of the Volcanoes. For more information about Ecuador's volcanoes, see Global Volcanism Program (Ecuador).