I'm in Texas, where a total solar eclipse is happening on Monday, and people are gathering from all over to watch it. So what's so special about it? An eclipse is when the moon lines up exactly between the sun and the Earth. Everything goes dark, and it's an amazing spectacle. Total solar eclipses do happen once every couple of years, but often they go over oceans or the North Pole, so there's no one around to see it. This one's being called a once-in-a-century event because it goes right over North America, so millions of people will get to experience it. It'll go from Mexico through Texas, the Midwest, then upstate New York, and into New England. But even if you're in what's called the path of full totality, there's no guarantee you'll get the perfect view. So everyone's watching the weather forecast here, hoping for a nice, clear day.