Prague, Czech Republic:
Prague’s Astronomical Clock (Czech: Pražský orloj), located in Prague’s Old Town, was first installed in 1410. It is the third oldest astronomical clock in the world, and the only one currently in working order.
Inside the large black outer circle lies another movable circle marked with the signs of the zodiac which indicates the location of the Sun on the ecliptic. The signs are shown in anticlockwise order. In the photographs accompanying this article, the Sun is currently in Aries, and will be moving anticlockwise into Taurus next.
The displacement of the zodiac circle results from the use of a stereographic projection of the ecliptic plane using the North pole as the basis of the projection. This is commonly seen in astronomical clocks of the period.
The small golden star shows the position of the vernal equinox, and sidereal time can be read on the scale with golden Roman with numerals. Zodiac is on the 366 teeth gear inside the machine. This gear is connect to the sun gear and the moon gear by 24 teeth gear. – Wikipedia