It is unknown who invented the cuckoo clock and where the first one was made. It is thought that much of its development and evolution was made in the Black Forest area in southwestern Germany (in the modern state of Baden-Württemberg), the region where the cuckoo clock was popularized. These clocks were exported to the rest of the world from the mid-1850s on. Today, the cuckoo clock is one of the favourite souvenirs of travelers in Germany, Switzerland, Austria and North Eastern France. It has become a cultural icon of Germany.The mechanism to produce the cuckoo call has been in use since the middle of the 18th century and has remained almost without variation.