The Astronomical Clock in Prague, also known as the Prague Orloj, is a magnificent and intricate piece of medieval engineering. This world-renowned marvel rests in the heart of Prague, in the Old Town Square, and has been an emblem of the city since its installation in 1410, making it the third-oldest astronomical clock in the world and the oldest one still operating. This marvel was designed and built by the Imperial clockmaker Mikuláš of Kadaň and Charles University professor Jan Šindel. The clock was later improved by Master Hanuš in 1490, who added the calendar dial beneath the astronomical dial and the animated figures, which are one of its most captivating features. The clock itself is composed of three main components: the astronomical dial, representing the position of the sun and moon in the sky and displaying various astronomical details; "The Walk of the Apostles", a clockwork hourly show of figures of the Apostles and other moving sculptures; and a calendar dial with medallions representing the months. The exterior of the clock is a testament to the Gothic architectural style of the period. The clock face is adorned with intricate, hand-painted zodiac signs and surrounded by beautifully sculpted stone figures of allegorical virtues including Vanity, Greed, Death, and Lust. On the hour, every hour, a small trap door opens and Christ marches out ahead of his apostles, while the skeleton of death tolls the bell to a defiant statue of a Turk. Below the Astronomical Clock are 12 medallions with the signs of the zodiac, added by Josef Mánes in 1865. The interior of the clock, although not open to the public, is a complex arrangement of gears, wheels, and counterweights. The clock's inner mechanisms were crafted from local, durable wood, which has been a significant factor in its long, functional life. The Astronomical Clock is not just a tourist attraction, but a symbol of the rich history of Prague. The clock has been repaired and restored several times in its history, including significant repair work following damage in World War II. Today, it stands as a testament to the city's resilience and its appreciation for art, history, and science.