Was it the Discovery Channel? Those are the same folks that said octopus will become simian-like and sharks will have pulsing bio luminescence along their bodies strangely timed to thrash metal music.

Bwaha

The pyramids are over 2000 years old.

Humans have been around for almost 2 million years.

I guess he means like, Cities now wont last that long?

i watched that docu and it was amazing!! and although it's hypothetical, their estimates really do make sense - without us here to keep care of them, water will keep getting into the cracks in our buildings, spread bricks apart to make way for plants to crawl in and in no time at all houses can be turned to rubble.
pyramids have lasted centuries because of egypt's climate, but in this specific documentary it hypothized that also without us here to care for them, over thousands of years sandstorms can bury entire pyramids!

they had the most breathtaking images of what skyscrapers would look like centuries after humans disappear: they become entirely over run by vines and plants, hundreds of levels of new ecosystems! the buildings are hypothesized to be over run by mostly birds and cats! it's what my dreams look like.

it was all pretty humbling and actually relieving to see that no matter how much we fuck up this planet (as long as we don't blow huge chunks out of it) it only takes about a few thousand years before animals and plants take total control again.
everyone should watch it!