Commerce Building flag.
"100th Anniversary -  Herbert C. Hoover Building," <a href="//commons.wikimedia.org/w/index.php?title=United_States_Department_of_Commerce&amp;action=edit&amp;redlink=1" class="new" title="United States Department of Commerce (page does not exist)">United States Department of Commerce</a> <a rel="nofollow" class="external autonumber" href="https://www.commerce.gov/opa/photo/DOC_100/HCHB_Gallery.htm">[1]</a>