On the River Usmacinta in the jungle about eight miles from Bonampak in Mexico, theres a Mayan ruin called Yaxchilan. Archaeologists have studied it for over a century. In 1989, James O’Kon, a civil engineer, noticed a mysterious mound of rocks which he thought was a part of a bridge. In order to prove his thesis, he used computers to integrate aerial photos, archaeological studies and maps to create a three-dimensional model of the sight to determine the exact positioning and dimensions of the bridge. As a result to his work, he discovered that the Maya had constructed the longest bridge span in the ancient world in the 17 century ce. 
The bridge was 600 ft long, and consisted of a hemp rope suspension with two piers and three spans. It connected Yaxchilan in Mexico with its agricultural domain in the Peten. Aerial photos have located a twin support pier on the opposite side of the river. Archaeologists assumed that the remains of a pier 12 ft high and 35 ft in diameter was a pile of rubble.