The term 'You Must Remember This' can be summarized by two crossword solutions: ALAMO (5 letters) and THEALAMO (8 letters). The ALAMO was a fort in San Antonio, Texas, that was the site of a famous battle during the Texas Revolution in 1836. The Battle of the ALAMO was a 13-day siege by Mexican forces led by General Santa Anna against the Texan rebels, who were ultimately defeated. The phrase 'You Must Remember This' is often used to refer to the importance of remembering the sacrifice of those who fought and died at the ALAMO.