Londinium was founded by the Romans almost 2,000 years ago, shortly before AD 50. Roman London was built on a "greenfield" site which is now occupied by the City of London and north Southwark. The early frontier town was an immediate success and was occupied for almost four centuries. For much of this time Londinium thrived, despite disasters that included destruction at the hands of Boudica, widespread fires, economic problems and political crises. Although abandoned in the 5th century, Londinium's layout determined the siting and shape of the medieval City of London and hence the modern metropolis. Over the centuries London's ground surface has risen inexorably and as a result Roman streets and buildings lie buried up to seven metres below the modern street level. This map graphically presents our most up-to-date knowledge of that lost world: the Roman city's topography, plan and appearance, including its roads, waterfronts, public buildings, houses and defences. Roman remains are accurately located and superimposed on the modern street plan, with visible features indicated. The accompanying guide, on the reverse of the map, provides a descriptive history of Londinium and illustrations of important sites and finds, many of which can be seen in the Museum of London galleries.