The United States Geological Survey, the agency responsible for charting the nation's topographic ups and downs, debuted a new online tool that allows users to pull up maps through the ages for different geographic locations and layer them for a neat compare-and-contrast effect. The easy-to-use feature lets you search by location, click a point, and see what maps are available for the area. You can then overlay them and adjust the transparencies to see change over time, especially when it comes to urbanization. You can also download the full-size files of the old maps, in case you need a super cool new desktop wallpaper.
· Nerd Out With 19th-Century New York City Maps and More [Curbed NY]
· USGS Historical Topographic Map Explorer [Historical Maps]