Our holdings include hundreds of glass and film negatives/transparencies that we've scanned ourselves; in addition, many other photos on this site were extracted from reference images (high-resolution tiffs) in the Library of Congress research archive. (To query the database click here.) They are adjusted, restored and reworked by your webmaster in accordance with his aesthetic sensibilities before being downsized and turned into the jpegs you see here. All of these images (including "derivative works") are protected by copyright laws of the United States and other jurisdictions and may not be sold, reproduced or otherwise used for commercial purposes without permission.
Vintage photos of:
September 26, 1924. Washington, D.C. "Mysterious tunnel." A strong Hardy Boys vibe here. National Photo Company Collection glass negative. View full size.
UPDATE: While initial speculation (bootlegging, espionage) was soon dispelled by an eccentric insect expert's explanation that he had dug the passages "for exercise," historical evidence suggests that this was a tunnel of love. Or at the very least, bigamy.