This Bing Map lets you view historical maps of Berlin. The map features an innovative 'timescope' that you can drag over the modern map of Berlin whilst viewing the historical map through the timescope.
If you wish to view a different historical map of Berlin you can select a date from the bottom of the timescope. It is also possible to adjust the transparency of the historical map to view the modern map beneath. On the right hand side of the map are quick links to some of Berlin's top sights.