根据下面提供的一篇文章，编辑出一段开头和结尾具有连贯性的摘要，长度为3到4句话。
文章：Why Do We Eat Popcorn at the Movies?
来源：National Geographic

Popcorn and the movies go hand-in-hand, but when and where did this perfect pairing originate? In the early days of cinema, theater owners didn't want to spend money on expensive snacks for their patrons. But savvy popcorn vendors had other ideas, and began selling their cheap, easy-to-make treat outside of movie theaters. Discover how popcorn became a staple of the movie-going experience in this entertaining video.
Popcorn has become a quintessential snack for moviegoers, but where did it come from? According to National Geographic, during the early days of cinema, theaters didn't want to spend money on snacks for their patrons, but popcorn vendors saw an opportunity to sell their cheap snack outside of the theaters. This tradition has continued for over a century and is now a staple of the movie-going experience. Watch the video to find out how popcorn became synonymous with movie theaters.