The U.S. Postal Service has released a stamp to commemorate the total eclipse of the sun that will take place Aug. 21.

The eclipse will first be seen in the Northwest and then sweep across the continent toward the Southeast.

A total eclipse sweeping across the continent hasn't happened since 1918.

The new stamps marking the upcoming event feature thermochromic ink. When you hold your thumb or something warm on the stamp, it reveals the moon in front of the sun instead of a black circle.

Kids will enjoy playing with the eclipse stamps. Bay News 9 let some children at the Explorations Children's Museum in downtown Lakeland give them a try. They had fun showing them to adults and showing other children how the stamps worked.

The stamp uses a picture of a total eclipse of the sun taken by an astrophysicist in Libya in 2006.

The back of a page of the eclipse stamps shows a map of the narrow path of the total eclipse.