A solar eclipse is happening today. Here’s what you need to know before looking up.

Skywatchers across parts of the Northern Hemisphere will have a chance to witness a solar eclipse on Wednesday, Aug. 12, though what they see will depend largely on where they live. While a total solar eclipse will sweep across parts of Greenland, Iceland, Spain and a small portion of northern Russia, millions more people in North America, Europe and Africa are expected to see a partial eclipse, according to NASA.