ELi5 : Why does it seem a lot of archeology began so recently in the 20th and 19th centuries? Why weren’t we digging up stuff much earlier?

Question

It seems many of the most important archeological findings were in the 20th and 19th century. Why did humans wait so long to start digging stuff up?

In: 961

Answer 1

I’m from up near Hadrian’s wall. Loads of old buildings (farms, churches etc) contain stones from it. If you’re living hand to mouth and you need building materials of course you would help yourself to a field full of pre-cut blocks.
It would have held no significance as only a few hundred years after they left the locals had forgotten who even built it (the historian Bede calls it the Pict wall in the 7thCent)