It's incredible they could make mechanical marvels like this clock 500 years ago.
The writers of Back To The Future
were inspired to fashion Doc Brown's time travel based on Einstein's breakthrough in the development of the theory of relativity inspired by the clock.
The film's time travel sequences are based at a clock tower with the DeLorean time machine driving toward the tower to gain it's power to move through time from a lightening strike, the tower being the highest point in the town. The Bern tower was initially built as a gate tower for Bern's fortifications when it was built around 1218–20, 52 ft in height. Later, it was heightened by 23 ft to maintain it's vantage point as Bern grew. Through it's history, funds for maintenance, restorations and so forth have been solicited in Bern, as was the case for the preservation of the clock tower in the movie.
Christopher Lloyd based his character, Doc Brown- whose dog was named Einstein- in part on Albert Einstein's mannerisms and idiosyncrasies, and the movie made references to black holes. After the dog travels into the future during an experiment, Doc Brown compares his watch to a watch placed on the dog to show difference in time, illustrating what Einstein had described in his inspiration; a moving clock versus a stationary clock; the one in motion moving more slowly.
Interestingly enough, although Michael J Fox's character, Marty McFly's travel back in time was set to 1955 to make chronological sense given the age of the characters, Albert Einstein died in 1955.
Some great videos of the clock in action here:https://www.youtube.com/results?search_query=zytglogge+clock+tower