Watch UFC’s all-time biggest upsets, including Holly Holm’s iconic head kick knockout of Ronda Rousey

Throughout the nearly three-decades of the UFC, there have been a handful of unforgettable and shocking upsets inside the octagon.

On Friday, the UFC released a video on their YouTube channel highlighting the fights that stunned the MMA world, which includes a slew of UFC world title changes.

The video kicks off with, more than likely, the most shocking result in the history of the promotion, as Georges St-Pierre defended the welterweight championship against Matt Serra — who earned his opportunity coming off of The Ultimate Fighter reality show. Despite nobody giving the nearly +900 underdog a chance, Serra became world champ with an incredible first-round knockout in the main event of UFC 69 in April 2007.

Additionally, the upset highlight-reel included the +830 underdog Holly Holm delivering one of the UFC’s most legendary knockouts as she stopped Ronda Rousey with a vicious head kick to win the women’s bantamweight title at UFC 193 in November 2015.

Check out the full slate of incredible upsets in the video above.