HyperCities is a layered history application built on the geolocation technology that powers Google maps. It allows the user to view a series of historical maps overlayed on the map of the modern city. It also links areas of the map to scholarly works, photos, family geneologies, and interviews on corresponding parts of the map.

HyperCities forms an interesting bridge between hypertext compendia and the layered geo-temporal ideas behind augmented reality and promises to be a valuable resource for students and scholars.