<Tr> <Th> Roller coasters </Th> <Td> 9 </Td> </Tr> <Tr> <Th> Website </Th> <Td> Six Flags St Louis </Td> </Tr> <P> Six Flags St. Louis, formerly Six Flags Over Mid-America, is a theme park located in Eureka, Missouri . The park opened on June 5, 1971 and features eight themed areas as well as numerous attractions and live shows . The adjacent Hurricane Harbor water park is free with park admission . The park brands itself as "Missouri's Coaster Capital". </P> <P> The park opened in 1971 as the third theme park of the Six Flags chain and is the only one of the three parks completely built, owned and operated by Six Flags . </P>

When did six flags over mid america open