The phrase “tying the knot” is synonymous with getting married. Although the words can represent the symbolic joining of two lives together, in some cultures, getting married actually requires tying a knot. The custom traces its origins to an ancient Babylonian tradition in which threads from the clothes of both the bride and groom were tied in a knot to represent the couple’s union. Other cultures have embraced this tradition, and couples tie ceremonial knots during their wedding ceremonies.