英語聽力：自然百科 馬丘比丘

The ancient city of Machu Picchu attracts visitors from all over the world. The most famous archaeological site in Peru, this Inca ruin floats among the clouds, 2,000 feet above the Urubamba River that runs below, and 7,700 feet above sea level. Historians believe the Inca began building Machu Picchu around the 1450s, but because they left no written records behind, no one knows exactly what their purpose was.

"The Inca royal family would go there for different kinds of ceremonies, and we do know that the Incas had a very strong ritual element there. There are some who think it maybe was just a retreat—they went there to have a nice, you know, retreat from all the hubbub of the capital city of Cusco."

But within a hundred years after the Inca began building this impressive city, they started to abandon it.

"Machu Picchu is probably abandoned or began to be abandoned already before the Spanish came. And that's because around 1525, there was a civil war."

After the Spanish arrived seven years later in 1532, the Inca deliberately burned the forest around Machu Picchu.

"They burned it because the foliage regrows and completely covers it and made it virtually impassible."

Perhaps thanks to the Inca's efforts to hide the city, the Spanish never found Machu Picchu. It was lost to the wider world until geographer Hiram Bingham rediscovered it in 1911. Over the last century, archaeologists have learned that Machu Picchu was also the hub of a large network of Inca sites.

"So the picture of Machu Picchu’s being an isolated ruin on this ridge is really incorrect. There are a whole series of sites that lead to it."

This series of sites has been described as a pilgrimage trail, but the Inca's ultimate plan for these places remained a mystery.

"It's part of a big system that was being built up by the, by the Incas. And it wasn't finished. We know there were things that were abandoned. So we don't know ultimately what that would, that whole area would have looked like, if the Incas did inhabit it, say, for another hundred years."

In 1983, Machu Picchu was named a UNESCO World Heritage Site. As archaeologists learn more about what happened here, new questions continue to arise, guaranteeing that Machu Picchu will remain a place of mystery for years to come.