A Radiolab series called Limits examines how far humans can push themselves in a variety of ways. In one episode, entitled “Limits of the Mind,” hosts Jad Abumrad and Robert Krulwich explore the outer boundaries of memory, focusing on the story of 1920s Russian journalist Mr. S., (Solomon Veniaminovich Shereshevsky, to be precise), who had a memory so elastic so as to be almost without borders. Mr. S., who was the subject of a book and became a popular mnemonist who performed at circuses, suffered from a neurological disorder known as Synesthesia, which was responsible for his remarkable recall and many of his problems in life. (Thanks Atlantic.)