There is a central axis between the Albert Memorial in Kensington Gardens to the north and the central portal of the south façade of the Natural History Museum. The Royal Albert Hall, Royal College of Music, the former tower of the otherwise-demolished Imperial Institute (now the Queen's Tower of Imperial College London) and the 1950s rear extension to the Science Museum are all aligned on this axis, which cannot be seen on the ground. This regular geometric alignment of Albertopolis can be observed readily only from the balconies of the Queen's Tower (very rarely open to visitors), although the northern part can be glimpsed from the top floor of the Science Museum.