April 5 has witnessed several significant events in US history that highlight the country's political, scientific, and military evolution. In 1792, President George Washington exercised his first presidential veto, rejecting a bill on congressional seat apportionment, which set a precedent for executive power. The Mendenhall Order of 1893 established US customary measurements based on metric standards, promoting international scientific alignment. The death of military leader Douglas MacArthur in 1964 marked the loss of a key figure from World War II and the Korean War. In 1986, a bombing at a West Berlin nightclub killed an American serviceman, prompting US airstrikes in retaliation against Libya. Finally, in 1991, the Space Shuttle Atlantis launched on mission STS-37, deploying the Compton Gamma Ray Observatory, which significantly contributed to the study of high-energy phenomena in space.