The Moray Terraces Were a 15th Century Incan Agricultural Research Station

Fifty kilometers (31 miles) northwest of Cusco, the historic capital of the Inca Empire, lies a peculiar sight: enormous terraces descending into the ground.

Located on a high plateau 3,500 m (11,500 ft) above sea level, at first glance, the site looks like an ancient Roman amphitheater, but it wasn't built for entertainment purposes. Welcome to the Moray Terraces.

Living at the top of the world

The series of terraces descend into the ground 30 m (98 feet ) deep and 220 m (722 feet) across. That depth, along with the orientation of the terraces to the sun and wind, means that there is a temperature difference of as much as 27° F (15° C) between the topmost and bottom most terraces.

RELATED: THE MYSTERIOUS AGRICULTURAL TERRACES OF THE INCAS

This temperature difference corresponds exactly to differences in temperature experienced at various elevations within the ancient Inca Empire — from sea level to the Andean highlands.

When scientists examined the soil on the various terraces, they determined that it came from different locations within the Incan Empire. This led to the inescapable conclusion that the Moray Terraces were an enormous agricultural testing station, with each level having its own microclimate.

The Inca were known to modify and hybridize crops, making them better suited for human consumption. Peru is the original home of the potato, and it boasts over 2,000 separate varieties of potato.

It's also possible that the terraces were used to help domesticate and acclimatize crops. Seeds may have been planted at the lower, and warmer, terraces, then transplanted onto the higher, and colder, terraces until plants that could survive at high altitudes had been bred.

University of Utah professor, Rebecca Horn, said, "The Andean people lived in extremely challenging environments, with extreme slopes, high altitudes, and dramatic changes in diurnal temperatures. They were able to expand their agricultural acreage through the use of very sophisticated agricultural practices. These included terracing, irrigation, and the creation of microclimates and anti-erosion techniques."

Who were the Inca?

The Inca Empire existed from 1438 to 1533 over a large part of western South America. Centered on the Andes Mountains, the empire extended over Peru, southwest Ecuador, western and south-central Bolivia, northwest Argentina, and a large part of what is today Chile.

The official language of the Incan Empire was Quechua, and they worshiped Inti, who was their sun god. The Incas considered their king to be the "son of the sun."

The administrative, political and military capitol of the empire was the city of Cusco. In spite of their obvious sophistication, the Incas did not have the wheel, nor had they mastered the making of iron. Most critically, the Incas lacked a system of writing.

Instead of writing, the Inca used knotted strings called quipu, which they used to keep records and communicate. The Inca produced monumental stone structures, created an extensive road network that reached all corners of the empire, and made finely-woven textiles.

University of Utah professor Hugh Cagle described the Inca as "exceptional engineers and craftsmen" who were able to create a system of roads spanning over 3218 kilometers (2,000 miles) of their empire.

Cagle also noted the Inca's ability as stone masons, who were "able to fit enormous stone blocks together without mortar, and the blocks fit perfectly together, with nothing joining the stones." The big question remains: without iron, how did the Inca sculpt the blocks?

The Inca had no known money or markets. Instead, goods and serves were traded among individuals and groups. The Inca were most known for their agricultural innovations and irrigation technology, the Moray Terraces being just one example.

Until 2010, the Moray Terraces had never flooded despite often enormous rainfall. Scientists speculated that the Inca must have installed underground channels beneath the lowest terrace that channeled the rainwater away.

Then, in February 2010, torrential rains caused the stone and compacted earth along the east side of the Moray Terraces to collapse. A temporary wooden scaffold was erected to prevent further collapse, but to date, a lack of funds has inhibited restoration work.

Machu Picchu

Around 1450, the Inca built Machu Picchu near Cusco as a summer estate for their emperor Pachacuti (1438 - 1472). Incredibly, Machu Picchu was never discovered by the conquering Spanish, and remained unknown until 1911 when American explorer Hiram Bingham discovered it.

In 1948, Bingham's book about the discovery of Machu Picchu, Lost City of the Incas, became a best seller. In 1983, Machu Picchu became a UNESCO World Heritage Site, and in 2007, it was voted one of the New Seven Wonders of the World in an Internet poll.

The end of the Inca

In 1526, the Spanish conquistadors led by Francisco Pizarro first reached Inca territory. Returning to Spain in July 1529, Pizarro received approval from the Queen of Spain to conquer the Incas.

When the conquistadors returned to Peru in 1532, a war of succession was raging between the sons of the current Inca emperor, Huayna Capac. Pizarro only had 168 men, 27 horses and a single canon, but his men also carried smallpox, influenza, typhus and measles with them. After multiple skirmishes, the Inca were finally defeated by the Spanish in 1572.

If you want to see the Moray Terraces yourself, tour buses leave from Cusco. There are also taxis, which are more expensive. Before visiting the Moray Terraces, you should gradually acclimatize to the 3352-meter (11,000-foot) elevation.

The Incas adapted to the altitude by having almost a third larger lung capacity than average humans, slower heart rates, 4 pints (2 L) more blood volume, and double the amount of hemoglobin, which transfers oxygen from the lungs to the rest of the body.