To commemorate the momentous occasion, historical writer Michael Beschloss shared one of the earliest photos of Philadelphia with his more than 75,000 Twitter followers.
We decided to follow Beschloss' lead, and hunted down early photos from a handful of other big cities across the United States.
Check out these early photos from 12 big cities below.Philadelphia, Pa.
A view of 8th and Market streets downtown. Beschloss says it's one of the earliest photos of the city, courtesy of Free Library of Philadelphia.