Imagine one second you are enjoying a quiet day, and the next, you are surrounded by dozens of people on their feet dancing.
That's just what happened Saturday in Rapid City's Main Street Square. More than 75 people participated in a flash mob.
It was part of a nation - wide effort. In more than 200 cities across the country, people did the same dance at the same time.
Everybody participating go to learn and practice the moves from an online video before performing them for real.
The idea was put together by the Body by Vi 90-day challenge, who hopes to promote weight management and healthy nutrition.
The dance featured a number of songs, starting with the "It's Not Unusual" dance performed by Carlton from "The Fresh Prince of Bel Air."