Pedicabs wait for passengers in front of Mexico City's Metropolitan Tabernacle. "DF," as the city is called by local residents, has taken many measures to improve its air quality since the 1990s.

Monte Albán is a former Zapotec city in the state of Oaxaca and a UNESCO World Heritage Site. Some 400,000 people speak Zapotec languages in Mexico today.

Waterfalls inside Palenque's Mayan archaeological site in Mexico's southern state of Chiapas.

Tablet showing the ancient Mayan writing system at Palenque Archaeological Ruins, a UNESCO World Heritage Site.

Akumal, a small town south of Cancun in Mexico's Caribbean coast (also known as the Riviera Maya) is famous for its beautiful beach and sea turtle refuge.

Antigua (elevation: 1530 m) was the capital of a colonial region that spanned from the southern Mexican state of Chiapas to Costa Rica until an earthquake destroyed most of the city in 1773.

Volcanoes surround Lake Atitlán (elevation: 1560 m), Central America's deepest lake.

This sixteenth-century fortification, one of the oldest in The Americas, overlooks the largest sheltered harbor in the Caribbean Sea and is a UNESCO World Heritage Site. The citadel was last attacked in 1898 during the Spanish-American War, in which Spain ceded ownership of the island to the United States.

Puerto Rico's San José Church, the second oldest in The Americas (1532), housed the remains of Juan Ponce de León until the nineteenth century. Ponce de León was the island's first colonial governor.

Blue-footed booby on the small island of Isla de la Plata ("Silver Island"), off the coast of Ecuador. These peculiar sea birds are commonly associated with the Galapagos Islands, where more than half of the species lives.

The ancient Incan city of Machu Picchu (elevation: 2430 m), abandoned in the 16th century, was never found by Spanish colonizers and thus avoided the plunder and destruction that befell other Incan sites. UNESCO has called it "among the greatest artistic, architectural and land use achievements anywhere."

The Church of the Society of Jesus in Cusco (elevation: 3400 m)—former capital of the Inca Empire—was built on the foundations of an Inca palace in the 16th century.

Hundreds of macaws and parrots circle around the El Chuncho clay lick in the Tambopata National Reserve, which forms part of the Peruvian Amazon basin. The area, which can only be reached by boat, is unfortunately being deforested by illegal gold mining operations.

The Church of the Society of Jesus in Arequipa (elevation: 2380 m) is a beautiful example of Andean Baroque architecture.

The Salar de Uyuni in the highlands of southwestern Bolivia (elevation: 3656 m) is the largest salt flat in the world. The salt crust covers more than half of the world's lithium reserves.

The Atacama Desert (elevation shown: 2400 m) in northern Chile is one of the driest places in the world. The area has the largest deposit of sodium nitrate in the world and is rich in many other minerals, most notably copper.

The Eduardo Abaroa Andean Fauna National Reserve is a protected area located at altitudes above 4000 m in the most southwestern part of Bolivia.

The Eduardo Abaroa Andean Fauna National Reserve is a protected area located at altitudes above 4000 m in the most southwestern part of Bolivia.

Potosi's Cerro Rico ("Rich Mountain") was once largest silver deposit in the world and the main source of wealth for the Spanish Empire. At its peak in the 17th century, the city (elevation: 4067 m) had a population larger than London, Milan, or Seville.

The Calchaquí Valleys (elevation: 1683 m) in northwestern Argentina were a stronghold of indigenous peoples until the late 16th century.

Iguazu Falls, located at the border between Argentina and Brazil, is one of the widest waterfalls in the world.

This Argentinean road leading to the Chilean border is located some 20 km from Aconcagua, the highest mountain outside of Asia.

A large piece of ice collapses as the Perito Moreno Glacier advances. Only three of the 48 Patagonian glaciers are still growing.

Torres del Paine National Park, located in the Chilean Patagonia, is home to some of the most impressive sights in South America. Every year it receives over 100,000 visitors from all over the world.

Tierra del Fuego National Park is located at the southern terminus of the Pan-American Highway.