Dinos destroyed 65 million years ago, by a comet that was fallen on Earth. Scientists and geologists found the spot of the impact in the Golf of Mexico. The result of this impact was the end of the reptile Era of the Dynosaurus and the rise of the mammals. Without this impact we would have a different future, perhaps without the Evolution of the mammals we wouldn't had the Human Race..
Regarding Noah's flood, it is just a copy of an older Mythical Mesopotamian legend, the Gilgamesh Epic. Indeed we had varioius stories of Floods in human history, Greeks, Egyptians and this is a result of the Ice melting 10,500 years ago, that caused lot of floods. The story of Noah it could be true, since there was a flood in the Mesopotamian area, about 7000 years ago, when Etna volcano explode in Italy and created a tsunami, reaching Mesopotamia region. A region that is about 300 feet bellow sea level, so it can be easily flooded by waters.