Chicxulub Impact Crater (1980)

Chicxulub Impact Crater offers the definitive proof that a 10-kilometer-wide asteroid ended the reign of non-avian dinosaurs 66 million years ago, killing 75% of species worldwide. Luis and Walter Alvarez discovered a 20-foot-thick iridium layer at the K-Pg boundary in 1980, which contains 160 times the normal abundance of this element. This single event triggered tsunamis 1,000 feet high and wildfires across entire continents—far exceeding the devastation caused by any volcanic eruption in Earth's history. It offers a 40% more complete extinction timeline than the Deccan Traps theory, with iridium spikes matched to the exact moment when dinosaur fossils vanish globally.