On September 29, 1967, the U.S. Post Office issued its first attached pair of stamps to have a continuous design. The stamps, officially titled Accomplishments in Space, were issued to honor the 9th anniversary of the National Aeronautics and Space Administration (NASA). The stamps were the first to be designed by renowned space artist Paul Calle. These stamps are also often known as the “Space Twins,” as they’re the first twin stamps ever issued by the U.S., with one design continuing across both stamps. The stamps picture a space-suited astronaut floating near the Gemini 4 Capsule. Launched on June 3, 1965, the objective of Gemini 4 was to assess the effects of prolonged space flight on both the crew and the spacecraft. Two secondary objectives included an attempt to rendezvous with another object orbiting Earth and the first-ever U.S. space walk, or Extravehicular Activity (EVA).