All along it was thought to be either an act of God or perhaps long, slow climate change, and that really changed in 1980, in this rocky outcrop near Gubbio, where Walter Alvarez, trying to figure out what was
A lo largo del tiempo se pensaba que era o un acto de Dios o quizás un cambio de clima largo y lento, y eso realmente cambió en 1980, en este afloramiento rocoso cerca de