In 1989 the airport authority announced plans to rebuild the existing terminals and add two runways. After an environmental impact study was released the following year, the cities of Irving, Euless and Grapevine sued the airport over its extension plans, a battle that was finally decided (in favor of the airport) by the US Supreme Court in 1994. The seventh runway opened in 1996. The four primary north–south runways (those closest to the terminals) were all lengthened from to their present length of . The first, 17R/35L, was extended in 1996 (at the same time the new runway was constructed) and the other three (17C/35C, 18L/36R and 18R/36L) were extended in 2005. DFW is now the only airport in the world with 4 serviceable paved runways longer than .