Walter Alvarez and his team made one of the most astonishing scientific discoveries of the twentieth century--that an asteroid smashed into the earth 65 million years ago, exterminating the dinosaurs. Alvarez had the first glimmer of that amazing insight when he noticed something odd in a rock outcrop in central Italy. Alvarez now returns to that rich terrain, this time to take the reader on an excavation of the earth's distant past. We encounter the volcanoes that formed the Seven Hills of Rome; majestic limestone mountains that formed millions of years ago under water; and the evidence that the Mediterranean Sea completely evaporated to a sunken desert, perhaps several times, and that continental plates once overran one another to form the Alps. In Alvarez's telling, all major geologic episodes are as dramatic as the great impact that killed the dinosaurs, even when they happen over eons and without huge creatures to witness them.--From publisher description.