... what really happened to the dinosaurs?

Can a rare metal on Earth be a clue to the demise of the dinosaurs? There are a number of theories behind this sudden mass extinction, some believe it was due to a large amount of volcanic activity that blocked out the sun for hundreds of years, other beieve it was the impact of extraterrestrial bodies like huge meteors. There are even those that believe the extinction was constructed by godly or extraterrestrial beings, so to make way for mammals and human like beings.