The Tate Modern was eventually introduced when it became clear in December 1992 that modern art from around the world and Britain was limited to too small a space in Millbank where it was then located.
The plan was to create the new home for modern international art (thereby creating more exhibition space and strengthening the identity of the modern international art) by 2000. In April 1994 the new location of Bankside Power Station was announced. One stand-out feature of the building for me was the huge roof light box providing the light source for the main part. This was to create more light on the main part of the building to show off the dramatic and massive display area. Another feature was its massive single chimney when it was built in two stages in 1947 and 1963.
The building when it was redesigned in 1995 retained much of its original design with subtle alterations and most notably the light roof box adding extra light. The building was redesigned by the firm Herzog & de Meuron after winning a competition for this privelege.