MOLA (Museum of London Archaeology) has been excavating, studying and documenting the physical remains of London past since the early 1970s. Twenty years ago they started compiling all of their information and results into a single digital framework, to keep track of the multitude of data coming in and to allow patterns of development to be analysed in a way that simply could not be done with analogue systems. Diverse mapping information and metadata is added to the MOLA GIS, including street layouts dating back to the Roman period, major historic properties, lost burial grounds, and importantly areas of past archaeological investigation, including details of the extent of previously excavated trenches. The archaeological features from all of the excavations MOLA has conducted since the early 1990s have been digitised and georeferenced and the artefacts found within them located within the GIS through an Oracle database. Today the MOLA GIS is a unique and constantly developing resource. It brings together information on the underlying geology and topography of London, pinpoints areas of archaeological potential, details the development of settlements, industry, trade and infrastructure and provides evidence of changing social circumstances; wealth, poverty and disease.