The last map of the Inca Road, considered the base map until now, was completed more than three decades ago, in 1984. It shows the road run­ning for 14,378 miles.

But ironically, it was the Inca Road that hastened the demise of its creators. When the Spanish reached the Pacific coast in 1532 the empire was weakened by internal fighting and smallpox.

Atahualpa, the last Inca emperor, was captured by Spanish conquistador Francisco Pizarro in 1532. He promised to fill a room with gold and another with silver as ransom for his freedom.

A new exhibit at the National Museum of the American Indian highlights the engineering prowess of the Inca, whose great road once spanned mountains, deserts and forests in 6 South American countries.

Jorge Anhalzer's team discovered an ancient Inca road matching Valverde's map, possibly leading to the lost treasure. Ziplining over a dangerous waterfall in Ecuador's Banos Canyon.