The famous clock in Prague is called the Astronomical Clock, or "Pražský orloj" in Czech. It is located in the Old Town Square and was first installed in 1410, making it the third oldest astronomical clock in the world and the oldest one still in operation. The clock features moving astronomical dial, zodiac signs, and a unique procession of the Twelve Apostles that occurs hourly. The Astronomical Clock not only serves as a timepiece but also demonstrates the medieval understanding of astronomy and timekeeping. It attracts tourists and locals alike, making it a significant landmark in Prague.