In the rugged, gorge-filled terrain of the Andes Mountains, there are places where roads alone would fail to provide adequate transportation. But, as was the case with most obstacles they encountered, the Incas had a solution: bridges.
Unlike the arched stone bridges built in Europe at the time, the Incas used rope to construct suspension bridges across mountain chasms, as they had long been experts at weaving materials from natural fibers. Since there were no wheeled vehicles, the rope bridges worked beautifully for foot traffic, conveying both man and beast with ease.
During bridge construction, large rope cables were formed from smaller ropes woven from llama and alpaca wool, as well as from grass and cotton. These were attached to stone structures on either side of the crossing. More of the thick cables were stretched to form handrails as well as the floor of the bridge, which was then covered with wood and sticks.
Longer than any stone bridge in Europe at the time, the Incan bridges spanned openings of at least 150 feet (46 meters). Travelers often crossed in the morning, as strong winds later in the day could cause the bridges to swing wildly like hammocks.
Because the materials that created the bridges were organic and biodegradable, they had to be rebuilt every year. Often, communities living near the bridges carried out this function.