Collecting belt buckles from nearly every nuclear power plant in the U.S. wasn’t the goal for Don Hildebrant when he obtained his first one. Over time, it just turned out that way.

One day years ago, Hildebrant came across a buckle from the nuclear plant where he worked, and it seemed before he knew it, he had collected more than 250 of them—some from plants that were never even completed. “When you look at the collection, you will see an interesting story of where nuclear power has been, and how far it has come,” he said.

To mark the International Day of Women and Girls in Science, the U.S. Postal Service today issued a commemorative Forever stamp recognizing influential nuclear physicist and professor Chien-Shiung Wu (1912–1997).

A great honor: The stamp was dedicated during a virtual ceremony that can be viewed on the Postal Service Facebook and Twitter pages. USPS official Kristin Seaver was joined for the ceremony by Vincent Yuan, a scientist at Los Alamos National Laboratory and son of the honoree; Jada Yuan, granddaughter of the honoree; and Brian Greene, professor of physics and mathematics at Columbia University. The stamp is available for purchase at Post Office locations nationwide and online.

“I am elated to have my mother honored by USPS on a postage stamp because I believe it goes beyond recognizing her scientific achievements; it also honors the determination and moral qualities that she embodied,” said Vincent Yuan. “It’s even more profound that the recognition comes from America, the country of her naturalization that she loved.”