The huge concrete estate on the hill above Sheffield station, built between 1957 and 1961 as "streets in the sky", with wide deck-access walkways meant to keep the community life of the slum terraces it replaced. It declined badly in the 1980s and 1990s, was Grade II* listed in 1998 (making it the largest listed building in Europe), and has been progressively restored by Urban Splash and partners since the late 2000s. The "I love you will u marry me" graffiti on one bridge became a city emblem, and the estate inspired the musical Standing at the Sky's Edge.
Wikipedia: Park Hill