Have you noticed that some of the athletes competing in the Rio 2016 Summer Olympics, including the famous 31-year-old swimmer Michael Phelps, have unusual dark red circles on their skin? It's not an allergic reaction, it's not love bites, it's not a cigar burn. It is a very special ancient therapy with glasses, which is supposed to reduce pain and is widely used by American athletes, and many celebrities have been walking around the world with unusual spots on their skin for a long time.
