Huge crowds await a total solar eclipse in North America. Clouds may spoil the view

Millions of spectators in the U.S., Mexico and Canada are eagerly anticipating the total solar eclipse. It's expected to be North America's biggest eclipse crowd ever, thanks to the densely populated path. But cloud cover is threatening to spoil the view for many. Clear skies are only promised in northern New England to Canada. During the eclipse, the moon will pass in front of the sun and obscure it for up to 4 1/2 minutes. The rest of North America will see a partial eclipse, weather permitting.