A NASA photograph taken by the crew aboard the ISS of the night view of the Korean Peninsula. North Korea, in the middle, is almost completely dark compared to neighboring South Korea (bottom right) and China (top left).
I found this picture with a caption saying this is door knobs found in coal. I believe it to actually be some type of coral or other formation under water. But would like some further advice to clarify what exactly it is! Any information will help!