You've seen them in real life at a game, or blazing through your monitor speakers as you've watched a broadcast. They're on their feet for at least 90 minutes, cheering, drumming, flag-waving, singing, and doing everything in their power to support their club from start to finish.
They're the MLS supporters' groups, the most devoted fans in the league.
Interested in dipping your toes into these colorful, exuberant waters? Or just wondering what the whole thing is about?
The scene varies from team to team, and from individual group to individual group. So here's a 2017 overview — a field guide, if you will — to some of the supporters' groups for each MLS team.