The 13th century Long Bridge in Bideford (spanning the River Torridge) by night.
You will notice the arches are of varying sizes. There are three theories why this is so. Firstly, each parish paid for an arch and the richer parishes could pay for a larger arch, secondly the stone bridge used the previous wooden structure as a sort of scaffolding and the wooden arches varied according to the size of the trees from which the timbers were cut and, thirdly the size of the arches varied according to where decent foundations could be found on the river bed.
Take your pick!