When the Ottoman ruler put out a request for bridge designs back in 1502, one of those who responded was none other than Leonardo da Vinci. As it turns out, da Vinci didn't get the job, but his visionary design sketch survived. Now, MIT researchers have used that sketch to build a scale-model using the same materials that would have been available in that era—and they say da Vinci got it just right, per a release from MIT. As Live Science explains, this was no ordinary bridge design: If it were built, it would have been the longest bridge of its day at about 920 feet long. (See a photo of the model and original sketch here.) "It's incredibly ambitious," says Karly Bast, who worked on the project as a grad student. "It was about 10 times longer than typical bridges of that time."
Bridges of the era typically used semicircular arches, but da Vinci opted for a single flattened arch, tall enough for a sailboat to pass underneath. The researchers used stone blocks to build their model, which was about 500 times smaller than the original design, and they determined it would have been held together by compression, not mortars or other fasteners. "It's the power of geometry," says Bast. "This is a strong concept. It was well thought out." The inventor also called for abutments that splayed outward for greater stability, likely because he knew the area was prone to earthquakes. A real-life version of the bridge exists in Norway, though that one makes use of modern material such as steel and concrete. The MIT project will be featured in a Nov. 13 program of NOVA on PBS. "It would have been an ancient architectural marvel," writes Andrew Liszewski at Gizmodo. (Read more Leonardo da Vinci stories.)