Wind-up toys have evolved from machine-made 19th century tin or metal mechanical figures. The mechanism for these playthings has been available since clockmakers manufactured the first timepieces. The earliest wind-up toys--custom-made automata powered by clockwork or spring-wound mechanisms--delighted Europeans of the 16th century. Often very elaborate and involving multiple actions, early automata entertained the very wealthy and were deemed far to delicate and sophisticated to be appreciated by anyone other than adults. In the 19th century, the mass-production of tinplate, spring-driven toys placed walking figures and moving vehicles within the reach of middle-class children. The wind-up toy remained popular for decades, and when plastic became available as an inexpensive, easily molded material in the mid-20th century, wind-up toys of plastic became even more ubiquitous. Manufacturers have increased their wind-ups' popularity by licensing the use of popular TV, movie, and comic characters for their toys. Wind-ups are so popular, McDonald's, Burger King, and many fast-food restaurants augment their meals with wind-up premiums.