Karlsruhe, Germany, Feb. 18, 1976: Spec. 5 David Montgomery, company clerk of the 517th Maintenance Co., ponders which of his assistants is which. The clerk-typist twins at Karlsruhe are Patricia (left) and Paula Malaya can be hard to tell apart, even for their boss.

Did you know today, Dec. 18 is National Twin Day? And although the editors made no mention of it when this photo was first published, the first one was celebrated the same year, in 1976! Check out the original article, and more photos of Patricia and Paula here.