Late last year, the Library of Congress added the 10,000th digital map to their online Geography and Map Reading Room. The 1607 chart of the North American coast by Samuel de Champlain (right) was described as such:

The unique document, originally intended for presentation to Henry IV, King of France, was compiled by Champlain (1567–1635), founder of New France (Canada). The map provides the first thorough delineation of the Canadian and New England coast from Cape Sable to Cape Cod.

These maps are an excellent resource for research as well as a great time-killer. Their collection of City and Town maps is a good place to start (this 1892 map of New York prominently displays the New York World Building, home to the World Almanac, when it was the world's tallest.)

Landmark in Map Digitization: Library Places 10,000th Map Online (Library of Congress)