Stretching 4,300 miles down the western edge of South America, the Andes Mountains are the world’s longest continuous mountain chain, anchoring the continent like a backbone and spanning seven countries, from Venezuela down to the southernmost tip of Chile and Argentina.

CAPITAL RECORDS: All three of the world’s highest-elevation capital cities are located in the Andes Mountains: Quito (Ecuador), La Paz (Bolivia), and Bogotá (Colombia).

Owing to its unique geology and diverse climates, the range has given rise to high levels of endemic flora and fauna, breathtaking landscapes, and civilizations that flourished under extreme conditions.

Ancient civilizations

The Andes Mountains are practically synonymous with the Inca Empire, and understandably so. The Inca civilization ruled much of this region from the early 13th century to 1572 (when it was conquered by the Spanish). During their heyday, the Inca built and expanded upon 25,000 miles of roadways that linked communities in modern-day Peru, Ecuador, Bolivia, Argentina, Chile, and Colombia.

Traces of the Inca have stood the test of time; many of those roadways remain, including the most well-known section, the 26-mile Inca Trail to Machu Picchu. Inca influence can also be heard in the Quechuan languages still spoken by millions of people today.

But the Inca were only one of many indigenous societies that flourished under extreme geographical conditions in the Andes highlands. In fact, they conquered and united other pre-existing societies, such as the Chachapoyas and Nazca in Peru, the Tiwanaku in Peru, Bolivia, and Chile, and the Cañari in Ecuador, among many others.

DREAD IN THE CLOUDS: The pre-Columbian Chachapoya people in northern Peru were known as the "Warriors of the Clouds," and they strongly resisted Inca rule.

Unique flora and fauna

The Andes chain—and in particular, the northern region known as the “Tropical Andes”—is a biodiversity hotspot where specialized species have adapted to the high altitudes and varying climates.

Astonishingly, of the 30,000 or so plant species identified throughout the range, about half are found nowhere else on Earth. Trees of the Polylepis genus, for example, characterize the mid- and high-elevation regions. Another plant, the Andean bromeliad, is the world’s largest bromeliad and can take 100 years to mature.

Birds, too, have adapted to the high altitudes. For example, about 140 hummingbird species can be found in the Andes, and research has discovered that these hummingbirds have evolved to thrive despite the low levels of oxygen. Other iconic species include the Andean Condor, whose excellent eyesight allows it to spot carrion from long distances, and the Andean Cock-of-the-rock, whose disc-shaped, bright orange crest distinguishes it from most other birds.

Many resident mammals have adapted coats that keep them warm in the high altitudes, such as the vicuña and guanaco (and their domesticated counterparts, the llama and alpaca), the chinchilla, and the mountain tapir.

BEAR-LY THERE: Paddington, the galoshes-wearing bear of children’s literature, was a spectacled bear. Real spectacled bears are endemic to the Andes (and don’t eat marmalade).

Breathtaking landscapes

Due to varying elevations and latitudes, the climate varies greatly throughout the Andes' path, with habitats ranging from lush rainforests and cloud forests to dry steppe, snow-covered peaks, and glaciers.

Argentina’s Aconcagua, at an elevation of 22,841 feet, is the highest peak not only in the Americas, but also in both the southern and western hemispheres. Other notable summits include Argentina’s Mount Fitz Roy, Chile’s Cuernos del Paine, Peru’s Salkantay, Colombia’s Nevado del Ruiz, and Cotopaxi and Antisana in Ecuador. Furthermore, many of the Andes' impressive peaks are actually volcanoes.

HAVING A BLAST: The highest active volcano in the world is Ojos del Salado (meaning "eyes of the salty one") on the Chile-Argentina border.

It's also worth noting that the Andes are home to the Amazon River's headwaters, as well as the the world’s highest navigable lake, Lake Titicaca, on the border of Peru and Bolivia.