Library of Congress
Loc: Washington as It Was
A large collection of historical photographs taken by Theodor Horydczak, a photographer who lived in the city from 1923 to 1959.
US Geological Survey
U.s. Geological Survey: Building Stones of Our Nation's Capital
Pictures and text describe the source and appearance of many of the stones used in the buildings and monuments in Washington, D.C. Included are a geologic time chart and an illustrated map of the geologic and geographic features of the...
Arlington Cemetery
Arlington National Cemetery Website: Pierre Charles L'enfant
This site from The Arlington National Cemetery contains a biography of L'Enfant (1754-1852) and information about the L'Enfant Monument. You will also find quotes about him, as well as by him. This site also includes several pictures.