Even 15,000 years ago, during the Paleolithic period, there were rock paintings depicting people wearing sandals. Of course, these were only the most basic high heels shoes, and they wore away
quickly. It wasn't until the thong sandal design came into play by the Ancient Egyptians that things really started getting practical.
Sandals are still very popular today, with hiking sandals, flip flops, polo sport sandals, and lots of different women's sandals and men's sandals. Strangely enough, with all of the different fashions over time, sandals weren't really considered a fashion statement though, until the twentieth century.
They're built for hiking, comfort, walking, beaches, and even sandals that look quite uncomfortable to walk in, but are appealing to look at. It may be supposed, then, that beauty of a sandal - as with everything else in fashion and practicality - is in the eye of the beholder.