A mosaic of images shows the white disk of the sun being blocked by the moon as seen from Guwahati, India, during the July 22, 2009, total solar eclipse.

Wednesday's solar eclipse had the longest duration of totality--when the sun completely covers the moon--of the entire 21st century. The unusual darkness of totality drives many so-called eclipse tourists to travel the world chasing the moon's shadow.

"It gets really dark and totality appears, and that's when it gets most spectacular," retired actuary and eclipse fan Rollie Anderson recently told National Geographic News.

"You see a black hole in the sky where the sun used be, and if there are birds around, they may stop chirping, because they think it's night."