![](http://www.alamy.com/thumbs/6/DC989000-616F-42D4-BBE2-054E7EDCBC6C/WP8E84.jpg)
Lock 18 (not Lock 20), in Great Falls MD. Although the Library of Congress site where this photo was originally found says Lock 20, close examination of this photo shows it is NOT lock 20 but Lock 18. See file:Lock 18 in Great Falls, historical, detail, from for more information. HABS says [Caveat: not accurate]: 1. Historic American Buildings Survey John O. Brostrup, Photographer August 6, 1936 10:00 A. M. VIEW OF LOCKS FROM SOUTHWEST. - Chesapeake & Ohio Canal, Lock No. 20 [sic], MacArthur Boulevard, Great Falls, Montgomery County, MD;
Size: 5273px × 3792px
Photo credit: © Alpha Stock / Alamy / Afripics
License: Licensed
Model Released: No
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