On Monday August 21, as predicted by the astronomers decades in advance, a solar eclipse will cut across the entire United States.

Even though the “totality” — the area where the sun is completely blocked out by the moon — is only 70 miles wide, the whole country (even Alaska and Hawaii) will experience a partial eclipse.

This is a sight few people – even veteran eclipse chasers – have seen.

In this video by NASA Goddard you can learn more about August 21st Solar Eclipse – the eclipse day.