If he weren’t so well known as a warrior and leader, Charlemagne’s would perhaps have been recognized by history for innovation in engineering. His troops may have been the first to invent the temporary bridge.  In 792 he commanded the design of a pontoon bridge suitable for crossing the Danube River. This method proved handy to an army on the move, and provided excellent security when the soldiers assembled the bridge, stormed across and then pulled it back over with them, not unlike the concept of a moat of a castle. Years later, the Bailey Bridge  — same concept – helped to win World War II.

A modern Bailey Bridge, from New Zealand Transport Agency, at nzta.gov.nz.

Building the World Blog by Kathleen Lusk Brooke and Zoe G Quinn is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.