In March 2014, the "Cosmos: A Spacetime Odyssey" exhibit opened at the National Geographic Museum in Washington, D.C. The display showcased clips from the show reboot, as well as memorabilia from current host, Neil deGrasse Tyson, and original host, Carl Sagan. Among the items was an article so iconic, it is forever linked to Sagan's persona: one of his signature turtlenecks [source: National Geographic].
While Sagan did wear a variety of clothing on "Cosmos: A Personal Voyage," he became as known for sporting a turtleneck, topped with a professorial blazer, as for his passion about the universe. On Carl Sagan Day, an unofficial annual holiday on Nov. 9, the anniversary of his birth, Sagan fans are encouraged to wear a turtleneck sweater with a brown jacket -- and to "celebrate the beauty and wonder of the cosmos he so eloquently described" [source: Center for Inquiry].