<Tr> <Td> American football Portal <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The community of Canton, Ohio successfully lobbied the NFL to have the Hall of Fame built in their city for two reasons: first, the NFL was founded in Canton in 1920 (at that time it was known as the American Professional Football Association); second, the now - defunct Canton Bulldogs were a successful NFL team based in Canton during the first few years of the league . Groundbreaking for the building was held on August 11, 1962 . The original building contained just two rooms, and 19,000 square feet (1,800 m) of interior space . </P> <P> In April 1970, ground was broken for the first of many expansions . This first expansion cost $620,000, and was completed in May 1971 . The size was increased to 34,000 square feet (3,200 m) by adding another room . The pro shop opened with this expansion . This was also an important milestone for the Pro Football Hall of Fame, as yearly attendance passed the 200,000 mark for the first time . This was at least in some part due to the increase in popularity of professional football caused by the advent of the American Football League and its success in the final two AFL - NFL World Championship games . </P>

When was the pro football hall of fame built