I must mention the Romans their engineers were amazing. Firstly prior to the Roman legionnaires soldiers could walk over stone bridges. Roman soldiers would march over a bridge and the regular rhythm wave of their steps would shake the bridge apart.

Roman engineers worked out the cause and officers would order half the soldiers to march out of step so to counteract the shaking to protect the bridges, this was only 4,500 years ago . . .

During their northern conquests the Romans planned a river crossing, this river crossing was 999 feet wide. The Roman general ordered a boat bridge built in 10 days. This meant under combat conditions the bridge had to progress 100 feet every day in a swift flowing river using improvised materials.

This was achieved and the overall campaign a major success and strategic victory for the Romans. Ancient abilities were truly amazing ! ! !