The National Atlas provides “reference and outline maps of the United States that you can print or use online. The reference maps display general reference features such as boundaries, cities, capitals, major highways, rivers and lakes, and terrain. Outline maps showing county boundaries, State boundaries, capitals, or other basic features are also available.” The maps are provided in color, as GIFs and PDFs, but will apparently print out nicely in grayscale.
History
Hi-Res History
The National Archives provides an amazing resource in their new site the Charters of Freedom. High-resolution images of key U.S. historical documents have been made available to the world, including the Declaration of Independence, the Bill of Rights and the Constitution of the United States. Beautiful. Simply beautiful.
Cosquer Cave
Cosquer Cave “is the only painted cave in the world with an entrance below present-day sea level where [prehistoric] cave art has been preserved”.