In what ways have caves provided important clues about the past?

The cave drawings tell stories and they could tell how the dinosaurs died. +++ To clarify and qualify. Yes. some caves preserve human art, artefacts and sometimes mortal remains that shed light on the cultures using the caves, but we cannot know what stories the pictures tell beyond an intelligent guess of hunting themes. Also, the sentence is ambiguous by apparently linking the art and the dinosaurs. Not only were these reptiles all dead 65 million years before Man appeared, but there are very few if any known caves at all anywhere near old enough to have any evidence of dinosaurs' lives and deaths at all! To the best of my knowledge there have been few if any dinosaur remains found in caves; and they would have been parts of fossils eroded from their host rocks and washed into the caves in geologically quite recent times. So caves do not shed any palaeontological light on the KT Boundary mass-extinction at all. What caves DO provide is naturally-protected sedimentary and speleothem evidence for past climates, though, and a lot of modern cave research is focussed on this to help us understand climate change.