Arches have been used for centuries to build structures that supported heavy loads. Here are two examples. Above is a pedestrian bridge over Carroll Creek in downtown Frederick built about 5 years ago. Below is the Legore Bridge over the Monocacy River in the northern part of the county. James Legore built the bridge in 1900 to speed deliveries of stone from his quarry to customers in Pennsylvania. To see more geometry, go to Katney's Kaboodle.