As David Letterman signs off from the "Late Show" for the last time, take a look back at memorable late night hosts through the years.
Steve Allen -- "Tonight Starring Steve Allen" (September 1954-January 1957, NBC)
Kevin C. Cox/Getty Images
Kevin Winter/Getty Images
Mahesh Shantaram via Wikimedia Commons
U.S. National Archives
Scott Olson/Getty Images
Sign up for Breaking News, Daily Headlines, Severe Weather Alerts & more!