10 Amazing Google Earth Add-Ons

Content in Google Earth doesn't always have to focus on in-the-present information--it often allows users to do a little time traveling too. David Rumsey, a renowned cartographer, has amassed a collection of over 150,000 historical maps, 120 of which he has used to create a fascinating layer of maps that shows how the world looked between 1680 and 1930. The highlight is the world globe from 1790 (shown), which demonstrates how dramatically the borders have shifted for many countries, especially in prewar Europe and the Middle East. (Toggle Earth's default Primary Database layers to get a better view.)