https://www.scientificamerican.com/article/scientists-spot-giant-crater-hidden-under-greenlands-ice/

Earth hides its scars well; the planet has endured countless millennia of eruptions and collisions, but scientists are still stumbling upon the evidence of all that geologic drama.

Now, one such team has announced that it spotted a scar hidden below Greenland’s ice, a giant crater nearly 20 miles (31 kilometers) wide. The researchers said a giant iron meteorite likely created the mark by slamming into Earth sometime in the past 3 million years.