Layers of London
This is a rather lovely web-site, there are a number of different maps (or layers) which can be overlaid on a modern map of London. There is now a map of medieval London available, as well as a World War Two bomb map, Tudor London and a map before and after the Great Fire of London in 1666. The web-site is at https://www.layersoflondon.org/ and it’s free of charge.