City Geometries, the Odd Ruin, and Some Genealogical Burrowing
Hey I have that top book, as I read it in grade school. We are talking 60's. It was the first time I had read about any archeology and lost cities and I was hooked.
Yep, I had it too, and it got lost along the way somewhere. I find it very intertesting that Silverberg's main forte is tme travel science fiction... looking way back and way forward.
Ha! Before I scrolled down to the last picture, I said to myself -- hey! That looks like Mont St. Michel!