April 1 Holidays

April Fools’ Day‘s leading origin theory links it to the 16th-century switch from the Julian to the Gregorian calendar, when people unaware the new year had moved from late March to January were mocked as “April fools.” National Burrito Day is observed on the first Thursday of April, celebrating the flour tortilla-wrapped staple of Mexican and Mexican-American cooking. Assyrian New Year marks the beginning of year 6777 in the Assyrian calendar, celebrating the ancient Mesopotamian spring festival of Akitu. MLB Opening Day marks the ceremonial first pitch of the Major League Baseball regular season, a date American cities have treated as an unofficial spring holiday since the 1870s. A prank, a burrito, a 6,000-year-old calendar, and a first pitch.