Earth and Planetary Science library has scanned topographic map sheets from many countries and they are collected on DVDs as scanned JPG images.
These map sheets are useful for archaeological research, and the scanned images can be included in computer mapping projects or georeferenced into a GIS project. Their page reads "The following list includes topographic map sets digitized from the Earth Sciences & Map Library's paper collection or purchased in digital format. "Digital Topographic Map Sets" are offline. The CD-ROM and DVD discs do not circulate, either inside or outside of the library. Many of the following map sets are proctected under copyright. These digital files serve exclusively as the library's archival copies."
A very useful resource, but you must visit in person and request the necessary map sheets.