Rod Serling's The Twilight Zone was a pivotal series that revitalized the science-fiction genre with now-iconic episodes such as 'Time Enough at Last,' 'Will the Real Martian Please Stand Up?' and 'Nightmare at 20,000 Feet.' The show originally aired in 1959, running for five seasons, and is considered to be one of the greatest television series of all time. While the show features incredible, thought-provoking writing from Serling and others, The Twilight Zone owes much of its success to the string of stars who appeared throughout the series.