1972 (MCMLXXII)was a leap year starting on Saturday of the Gregorian calendar (dominical letter BA), the 1972nd year of the Common Era (CE) and Anno Domini (AD) designations, the 972nd year of the 2nd millennium, the 72nd year of the 20th century, and the 3rd year of the 1970s decade.Within the context of Coordinated Universal Time (UTC) it was the longest year ever, as two leap seconds were added during this 366-day year, an event which has not since been repeated.