Up to 7 million people expect to gather along route for rare event

CHARLESTON, South Carolina - Twilight will fall at midday on Monday, stars will glimmer and birds will roost in an eerie stillness as millions of Americans and visitors witness the first total solar eclipse to traverse the United States from coast to coast in 99 years.

The sight of the moon's shadow passing directly in front of the sun, blotting out all but the halo-like solar corona, may draw the largest live audience for a celestial event in human history. When those watching via broadcast and online media are factored into the mix, the spectacle will likely smash records.