Cable Car Day is observed worldwide every January 17 to commemorate the 1871 patent granted to Andrew Smith Hallidie for the world's first practical cable car system. This day celebrates the invention of the cable car, a type of cable railway where cars are hauled by a continuously moving cable. Hallidie's notable creation, the Clay Street Hill Railroad in San Francisco, began service in the early 1870s and became the foundation for the city's iconic cable car system, which still operates today, albeit with only three of the original lines remaining. Celebrations often involve taking rides on cable cars in cities that still have such systems, including locations like Oakland, California; Perugia, Italy; and Zurich, Switzerland. Participants are encouraged to share their experiences on social media using the hashtag #CableCarDay.