Why is New York City strewn with large boulders? How did the Rocky Mountains form? And how is it possible that large, prehistoric fish fossils have been found in the plains of Kansas?

These questions—and more—are answered in the above video by NOVA PBS, which gives viewers a short overview of North America’s dramatic geological history. The main takeaway? Our continent once looked much different than it does now—and thanks to tectonic activity, its formation will continue to change far in the future.

For more details on North America's prehistoric past, check out NOVA’s new series “Making North America, ” which premiered on November 4 and will air again on November 11 and November 18 at 9 p.m. EST on PBS.

[h/t PBS]

Header image via iStock.