How to Make an Incan Bridge

Modern suspension bridges use a design similar to that used in Inca bridges.

When the Spanish Conquistadors arrived in Peru in 1532 they were surprised by the architectural marvels they came across, including rudimentary suspension bridges made of braided fiber cables that spanned Andean gorges. According to John Wilford of The New York Times, in the 16th century there were at least 200 of these fiber-braided suspension bridges, some using ropes that were as thick as a man's torso. You can visualize these Inca bridges and learn about how much weight they could potentially hold by making a model suspension bridge yourself.

Things You'll Need

• Newspaper
• 2-foot long by 4-inch wide cloth
• String
• Scissors
• Two chairs
• Tape

Instructions

1. Cut four strips of newspaper approximately 2 feet long by 2 inches wide.

2. Twist two of the strips together to make a cable. Twist the other two strips together also. These will be the railings of the Inca suspension bridge.

3. Cut 12 small holes along each long side of the piece of cloth. Make sure the holes are spaced equally and that they are approximately 1/2 inch from the edge of the cloth. The holes should be just wide enough to pass pieces of string through them. This cloth will be the bridge's walkway.

4. Cut 24 10-inch pieces of string.

5. Attach the newspaper railings to the cloth walkway using the pieces of string. Pass the pieces of string around the braided railings and down through the holes you cut in the cloth. Knot the ends of each string to secure them to the cloth walkway.

6. Arrange two chairs back-to-back and spaced about a foot apart.

7. Tape the ends of the bridge's newspaper railings to the top of the backs of the chairs.

References

• The New York Times; How the Inca Leapt Canyons; John Wilford; 2007
• Incas: Inca Roads and Bridges
• PBS: Nova Activity - Hang in There!