Our house is 94 years young. One of the joys of owning a "young" house, is you never know what you will uncover when you remodel in an area that has been previously remodeled.
When the deck was removed, one of the basement window wells was uncovered. Yesterday, the window was bricked in and the well filled, in preparation for having the concrete slab poured.
The second window well that had been covered previously was also found. It happened to be under the concrete steps that were poured sometime before the deck project. I imagine it happened in the 70's when the kitchen/pantry/breakfast room was remodeled into a large kitchen and 1/2 bath.
There was a mysterious concrete slab exposed when the deck was removed last week. It was broken up and (surprise!) the slab was covering either a cistern or, perhaps a coal chute.
Update: Current thinking is an old septic tank.
Fun and games!