Smallville is an American television series, which was developed by Alfred Gough and Miles Millar, based on the DC Comics character Superman. In the United States, the first episode of the series originally aired on October 16, 2001; the series finished its ten-year run on May 13, 2011, with 218 episodes. The first five seasons were broadcast on The WB; following The WB's merger with UPN in September 2006, Smallville continued to be aired on the new, combined network, dubbed The CW. All ten seasons are currently available on DVD in Regions 1, 2, and 4. Since the series premiered, it has averaged 4.47 million viewers per episode over its ten seasons.