National Cathedral under construction, Washington, D.C.

The Harris & Ewing, Inc. Collection of photographic negatives includes glass and film negatives taken by Harris & Ewing, Inc., which provide excellent coverage of Washington people, events, and architecture, during the period 1905-1945. Harris & Ewing, Inc., gave its collection of negatives to the Library in 1955. The Library retained about 50,000 news photographs and 20,000 studio portraits of notable people. Approximately 28,000 negatives have been processed and are available online. (About 42,000 negatives still need to be indexed.)

Carved from Indiana limestone, the cathedral's construction began in 1907 and took 83 years to complete in 1990. The structure comprises a 30-story-tall central tower, nine-bay nave, 215 stained glass windows, 112 gargoyles, including one of Darth Vader, an intricately carved wooden choir area, numerous chapels, and a crypt where President Woodrow Wilson and Helen Keller are buried. The cathedral's master plan was designed by George Frederick Bodley, a highly regarded British Gothic Revival architect of the late-19th and early-20th centuries, and was influenced by Canterbury. Construction started with a ceremonial address by President Theodore Roosevelt and the laying of the cornerstone. Planners hoped it would play a role similar to Westminster Abbey in the United Kingdom though intended as defined it as non-sectarian and nondenominational. The cathedral's design shows a mix of Gothic architectural styles of the Middle Ages. The cathedral was built with several intentional "flaws" in keeping with an apocryphal medieval custom that sought to illustrate that only God can be perfect. In 2016 two Confederate battle flag images were removed from stained glass windows commemorating the lives of Confederate generals Robert E. Lee and Stonewall Jackson installed in 1953. In 2017 stained glass windows honoring Lee and Jackson we removed completely.