Astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar used to travel 80 kilometers every week from the Yerkes Observatory to the University of Chicago, where he taught a course attended by only two students. When asked why he spent his time this way, the professor replied that they were very good students. In 1957, Lee Tsung-Dao and Yang Chen-Ning were awarded the Nobel Prize in Physics. The course taught by Subrahmanyan Chandrasekhar became the only course in history where all its attendees received a Nobel Prize.