Flash mobs began in 2003 as a social experiment organized through word-of-mouth but grew exponentially with the rise of social media. They involve large groups of people suddenly assembling in a public place to perform an unusual act and then dispersing quickly. While some flash mobs are meant as lighthearted surprises, others have turned violent, leading some governments to regulate or restrict large public gatherings. There is debate around whether flash mobs will remain a popular trend or fade as a passing cultural fad.