On Monday, August 21, the sun, moon and Earth will line up perfectly over many parts of the United States. This event, called a total solar eclipse, will turn day into night for a few minutes. Then the skies will slowly lighten again. For the first time in nearly 100 years, the total solar eclipse will be visible from the U.S. West Coast to the East Coast. The total eclipse can be seen along a path about 110 kilometers wide and reach across 14 states. Many areas near the main path should notice some darkness in the sky. A partial eclipse will extend up through Canada and down through Central America and the top of South America. This eclipse is expected to be the most ever studied and celebrated.