The Museum of London itself stands on the site of a Roman fort. It is one of the largest, and probably the most comprehensive urban museum on the planet, exploring all aspects of London city life from prehistoric times to the present day. The museum also periodically hosts various exhibitions on top of its permanent displays, which include the Great Fire Experience depicting the 1666 tragedy. Other galleries focus on public transportation, children and even the macabre. The museum also doubles up as a charitable association which is financed by various people and organizations.