What makes college football so exciting and full of energy?
In a word—fans.
It's all about the fans when it comes to college football.
Stadiums fill up to 100,000-plus with crazed fans locked shoulder-to-shoulder to go wild for their team every Saturday.
There are certain fan bases, though, that gain a reputation as a nasty group allowing no mercy for visiting opponents.
Sometimes it's all about one small chant; other times it's simply everything about these fans that strikes fear in their opponents' hearts.
Here is a look at the 15 most ravenous and boisterous fan bases in college football.