Union Square and St. Francis Hotel after Earthquake, San Francisco, News Photo - Getty Images
A HISTORY OF UNION SQUARE - FoundSF
Union Square San Francisco: Top Activities & Hotels
CALIFORNIA: San Francisco; Union Square, antique print 1907 Stock Photo - Alamy
History of Union Square - Books & Stories
San Francisco denies permits for SantaCon - Curbed SF
Map of San Francisco by Neighborhood (16 You Should See) - California Travel
A century of Union Square photos (with bonus mime action!)
Union Square, San Francisco, San Francisco - Book Tickets & Tours