Prague's astronomical clock, also known as the Orloj, is celebrating its 600th anniversary this year. Though the clock was added to later, 1410 is the year in which the clock was first established. Since then, the astronomical clock has watched over Prague from its position on Old Town Hall. Though the clock and the tower were damaged during WWII, it is now a Prague must-see sight. At every strike of the hour, the astronomical clock comes to life: two small doors open to reveal figures representing the 12 apostles and a bugler plays a tune. The clock's performance invariably draws a crowd.
For the 600th anniversary, an even larger crowd than usual gathered to watch a series of 3D projections that illustrated important moments in the clock's history. Accompanied by sound effects, the video projections recreated the clock's construction, destruction, and repair. Even if you weren't in Old Town Square on the night of October 9, 2010, you can still enjoy a video of this special event: Video of 600th Anniversary Celebration of Prague's Clock.
The official website of the astronomical clock's 600th anniversary is also of interest, though you'll have to use a translation application to read it if you don't speak Czech: 600 Years of the Orloj.
Prague Astronomical Clock photo credit: Kerry Kubilius, licensed to About.com