How do we know for sure that dinosaurs existed?

Question: How do we know for sure that dinosaurs existed?
- Keywords:
  dinosaur,
  exist
Asked by anon-240222 to Struan, Charlotte, Isabel, Douglas, David on 15 Mar 2020.
- Douglas Bray answered on 15 Mar 2020:
  
  The fossil records across the world are highly extensive. There have been fossils found on every continent that show evidence of dinosaurs.

Question: How do we know for sure that dinosaurs existed?