Tightrope walking has been a part of acrobats' performances for thousands of years. There was a time when tightrope walking was exciting enough on its own, but modern audiences always want something more. Now, some acrobats perform more impressive tricks on tightropes, like dancing or juggling. Other acrobats take their acts to higher and more dangerous places. Large circuses have high-wire acts, in which tightrope walkers perform on much higher wires in the air. For the extra brave, there are also skywalks, which are also very high, and long tightrope walks. Skywalks are the ones that make it into the record books. Skywalks also have a long history. Acrobats used to walk across Niagara Falls as a stunt, and it would attract huge crowds, but it got old. Over time, tightrope walkers would cross between buildings, such as in the film The Walk about a French acrobat who walked between New York City's World Trade Center Twin Towers in 1974. Others go even more extreme, like daredevils walking the longest wires in the world, some of those running between mountains in Switzerland. Some people skywalk to break records and some people do it for thrills, but everyone agrees it is very exciting to watch.