The pyramids were treated as a quarry over the millennia. Much of the outer casing and more was used to build medieval Cairo.

A sadly common fate for big stone buildings nearby any settlements. Lots of towers and castles in europe also ended up like that after their maintenance stopped.

From an alternative angle, it's not tragic but rather a triumph of the people who "actually" live there, to be able to repurpose old structures to modern use.

In Napoli, there's a set of pretty old (>300 years, I'd guess?) apartment buildings in the historic center, where if you view the buildings and curvature of the street from the sky or google maps, make a clear C shape.

The foundation of the buildings is a repurposing of a roman amphitheater. By the time that they began to convert the bottom 10 ft of the amphitheater into the basement of the homes, the amphitheater had been unused for centuries and the remaining high-quality building material had already been scavenged and repurposed for construction elsewhere in the city.

Naples, and many other "ancient" european cities that are still places inhabited majority by working people, are full of examples like this. It's kind of cool to see people living in a place where history is so overwhelming that it becomes banal.

I visited that amphitheater last year as part of the underground tour, really cool.

Might have read it at the Colosseum, but part of it were used by one of the noble houses to construct their Palazzo in Rome. Barberini if I remember correctly.