Thousands of years ago, a massive meteoroid seared through the Earth’s atmosphere and split into fragments over Greenland. Its pieces were later used for toolmaking by the Inughuit that inhabited northwestern Greenland. In other words: Inughuit people used space knives.

This fact, featured in a viral Reddit post on r/todayilearned, spurred an Endless Thread deep dive into a forgotten history of American exploration and exploitation abroad.