Geologists are still making discoveries in South Africa's Vredefort impact crater, the biggest on Earth.
In the abraded heart of South Africa's Vredefort impact crater lurk striking green-black rocks, some of the only remnants of a magma sea that once filled the gaping crater. (Image: NASA)
Geologists say they've discovered rocks long thought vanished, the youngest remains of the oldest and biggest impact crater on Earth.
