Popigai in northern Siberia: the ring is the eroded rim of a structure about 100 km across, cut through by the Popigai river. The target rock held graphite, and the shock turned it into diamond. Image: NASA Landsat.
Meteor Crater, Arizona, from the International Space Station: a 1.18 km bowl whose rim still stands above the plain 49,000 years after the impact. Image: NASA.
Gosses Bluff in the Northern Territory: the eroded central uplift of a crater formed 142 million years ago. Image: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team.
Pingualuit in northern Quebec: a 3.44 km circle holding a lake 267 m deep, with no inlet and no outlet. Image: NASA Earth Observatory, Landsat 7.
The Vredefort structure in false colour: the crescent of the dome is the surviving root of the impact, the rest of the original ring long since eroded. The Vaal River crosses it. Image: NASA Earth Observatory, Landsat 8.