The Cretaceous ended with the most famous mass extinction in history - the one that killed the dinosaurs. The extinction was caused by a massive meteor, that smashed into the Earth, this meteor was called the K-T Meteorite, to end almost all life inhabited on the prehistoric planet. Prior to that, it was a warm period with no ice caps at the poles. Much of what we now know as dry land - such as southern England and the midwest of the USA - was underwater, since sea levels reached their highest ever during this time. The Atlantic Ocean grew much wider as North and South America drew apart from Europe and Africa. The Indian Ocean was formed at this time, and the island that was India began its journey north towards Asia.