Of all the interesting things, the ancient Greeks used cork in the footbeds of their shoes -- way long before Birkenstock was a glimmer in anyone's eyes! This gladiator style, however, was one of Birkenstock's first styles. It has endured much like the wisdom of the Greeks. The footbed on this style has way more support I'm willing to bet. It is also lightweight and has four places of adjustment. Like the Greek sandals, it can be resoled again and again. Sustainable.