The Seventeenth of Tammuz, observed worldwide, is a minor fast day in Judaism that occurs every year on the 17th day of the Hebrew month of Tammuz. This day commemorates the breach of the walls of Jerusalem, which preceded the destruction of the Second Temple by the Romans. It also marks several other historical calamities, including Moses breaking the Twin Tablets of the Ten Commandments and the cessation of korban offerings at the Temple. The fast lasts from dawn until shortly after dusk, and while it does not impose the same restrictions as major fasts like Tisha B'Av, many Ashkenazi Jews choose to refrain from public entertainment, listening to music, and haircuts. Special prayers are added to the morning and afternoon synagogue services, marking the beginning of a three-week mourning period that culminates in Tisha B'Av.