Wow. Parallel lives.
The lot we bought to build on was densely overgrown and poison ivy heaven--we saw the perimeter and a bit of the wooded area but just trusted the rest would be ok. We knew it was once was the formal garden and rear lawn of a manor house that burned which lead to the property being divided and knew we’d become the owners of the 1880’s brick-and-stone water tower that served the property before the village had a water distribution system.
Upon clearing the growth, though, we found some surprises: a hand-dug well almost 20’ deep, an adjacent underground pump room, and a 10’ diameter concrete fountain! There was lots of buried, rusty piping for irrigation, too. Only the pump room was unsalvageable, so we filled it with all the big rocks we found when clearing for our lawn and...then we put a deck over it!