The Gasometers in the Simmering district of Vienna were originally built between 1896 and 1899 to supply town gas to Vienna. As technology changed, they fell out of use, and later were declared historic landmarks in 1978. In 1995, Vienna called for new ideas for the structures, and chose architects Jean Nouvel (Gasometer A), Coop Himmelb(l)au (Gasometer B), Manfred Wehdorn (Gasometer C) and Wilhelm Holzbauer (Gasometer D). Each mixed-use Gasometer is divided into residential, office, entertainment, and retail spaces. Complete in 2001, the Gasometers now have a village identity all their own, as well as an active online community.