Any dinosaur that survived the Chicxulub asteroid impact 66m years ago then faced a mega-tsunami that washed around the entire world and began as a mile-high wave, a study shows. It is no surprise that a 14km-wide asteroid slamming into the Gulf of Mexico would generate one hell of a tsunami but this is the first time anyone has worked out how big and how far-reaching it would have been. Using crater impact and global tsunami models, researchers show that within 10 minutes of impact a 1.5km-high wall of water was racing out of the Gulf of Mexico. Within 24 hours the shores of New Zealand – more than 10,000km away – were engulfed by towering 10-metre high waves and within 48 hours few coastlines remained untouched. Their results, published in AGU Advances, are corroborated by the jumble of rocks washed up by the tsunami in far-flung locations. A 66m-year-old rock mashup along the eastern shores of New Zealand had originally been attributed to earthquake activity but is now thought to be tsunami debris. The researchers estimate the tsunami was about 30,000 times more energetic than the Indian Ocean tsunami on 26 December 2004. “Any historically documented tsunamis pale in comparison with such global impact,” they write.