Did a meteor strike really kill all the Dinosaurs?

Very unlikely, it would have to be that big to effect the whole World that evidence would be visible. The crater would be hundreds of miles across. You'd see it from space even if it was forrested over. And how come so many species are alive today that predate Dinosaurs. Crocodiles for example. Myself i think a better explanation would be a virus spread by birds or flying insects. Something that could navigate the whole World. Anyone got any other ideas?