Canada experienced a massive meteorite strike some time in the last 70 million years that killed everything in the near vicinity.
Published in the journal Meteoritics & Planetary Science, researchers discovered an ancient ring-like structure in southern Alberta that they believe to be the site of the strike.
They believe the meteorite strike was large enough to leave an eight kilometre-wide crater, and would have produced an explosion strong enough to destroy modern-day Calgary.
The site, dubbed the Bow City crater, was discovered in 2009 by geologist Paul Glombick, who noticed a bowl-shaped structure while logging data from the oil and gas industry. The Alberta Geological Survey then moved in to explore further.
Research leader Doug Schmitt said much of the evidence needed to work out the origin of the structure had been eroded away by time and glaciers.
"We know that the impact occurred within the last 70 million years and in that time about 1.5km of sediment has been eroded," he said. "That makes it really hard to pin down and actually date the impact."
To work out where it came from, the team looked at seismic and geological evidence of the ring-like structure.
All that was left were the "roots" of the crater, which they established was probably 1.6 to 2.4kms deep when it first formed.
Graduate student Wei Xie said a meteorite strike big enough to make this crater would have had a devastating effect on anything living in the area: "An impact of this magnitude would kill everything for quite a distance. If it happened today, Calgary (200km to the northwest) would be completely fried and in Edmonton (500km northwest), every window would have been blown out.
"Something of that size, throwing that much debris in the air, potentially would have global consequences; there could have been ramifications for decades."