I started following Michael Beschloss on Twitter and each day brings more and more amazing pieces of history in photos. Beschloss' Twitter content is almost entirely a sharing of old photos he finds which run the gamut of sports, big US city scenes, battlefields, etc. The time frame can run from the 1800's to the 80's. So very engaging.
Here are two that caught my eye, both from Chicago the Soldier Field ski jump is 1954 and the planes over Grant Park was taken during the International Aviation Meet in 1911.
I have to just link the Grant Park aviation photo because the file extension is too large to download. But it's worth a look.
If you're on Twitter you might want to follow Michael Beschloss.