What is the August 21st eclipse?

There will be a total eclipse of the sun on August 21, 2017. What does that mean? And why it is important? This video explains more about the solar eclipse and why you should make plans to see it. It has been 99 years since an eclipse passed across all of the United States like this one. Which means people around the country will get to experience this incredible event only once in a lifetime.
We asked members of the Von Braun Astronomical Society in Huntsville, Alabama, what we should know about the Great American Eclipse of 2017. Listen to what they had to say.