The continental United States will experience a rare total solar eclipse on August 21.
The path of the eclipse will run from West to East for a period of about 90 minutes, and the total eclipse will be visible in 14 states, from Oregon to South Carolina. A total solar eclipse last crossed the entire country a century ago, in 1918.
Anyone in the world can watch
The U.S. space agency NASA will be live streaming the event, in which the moon will completely block the light from the sun.
But to commemorate the eclipse, you can also check out a first-of-its-kind postage stamp from the U.S. Postal Service.
On the new stamp, the black circular image of the eclipse is printed in thermochromic ink, which changes color when you touch it, and reveals an image of the moon. As the stamp returns to room temperature, the eclipse image goes to black again.
Other countries have released stamps printed with thermochromic ink. Great Britain, for example, issued such a stamp in 2001 to honor the centennial of the Nobel Prizes. However, the U.S. stamp is the first using the ink to show a solar eclipse.
The U.S. stamp was issued for the domestic first-class letter rate. It uses photographs of a full moon and of a total solar eclipse in Jalu, Libya, on March 29, 2006, both taken by Fred Espenak, a retired NASA astrophysicist and an eclipse expert.