How did dinosaurs get so cool? One of the reasons may have been that unlike us, they could evolve in a world where there was no USA. In the cretaceous period, much of North America was covered by water. This is what America looked like when it was home to dinosaurs like T. rex, Triceratops, Ankylosaurus or Deinonychus.
It's pretty wild what lived in that sea. The floor was covered in giant clams, up to a meter in size, and the accompanying 10m long sharks specialised in cracking the shells of large molluscs. There were mosasaurs like Tylosaurus, plesiosaurs, and fish like Xiphactinus.