The Postal Service dedicated its newest stamps, Endangered Species, on May 19 in South Dakota.

The images on the stamps are photographs of 20 species that exist today because of the protections of the Endangered Species Act, which marks its 50th anniversary this year.

“Just as there’s a story behind every U.S. stamp, there is a story behind every one of these animals,” said Peter Pastre, the Postal Service’s government relations and public policy vice president, who helped dedicate the stamps in a ceremony that took place in Wall, SD.

“We hope the Endangered Species stamps tell the story of hard work and hope, while raising awareness about endangered animals and wildlife, and the efforts to protect them,” he said.

The stamps feature photographs of 20 endangered species found within the 50 states and American territories and possessions, and also include two species living near U.S. borders.

Pastre was joined at the ceremony by Martha Williams, director of the U.S. Fish and Wildlife Service; Becky Dewitz, president and CEO of Great Plains Zoo; Jill Tiefenthaler, CEO of the National Geographic Society; and Joel Sartore, the stamp artist and National Geographic explorer and photographer.

Eric Veach, superintendent of Badlands National Park in South Dakota, was master of ceremonies.

Derry Noyes, an art director for USPS, designed the stamps with existing photographs by Sartore.

The images are a part of Sartore’s National Geographic Photo Ark project, an effort to document every species living in the world’s zoos, aquariums and wildlife sanctuaries.

The Endangered Species Forever stamps are available in panes of 20 at Post Offices and