The confluence of three events over the second half of 2013 -- three sellout cards at the MGM Grand Garden Arena in Las Vegas with a combined gate of $16.8 million -- shook up the sport of mixed martial arts in ways no one could have anticipated heading into the year.

On July 6, Chris Weidman rocked the MMA world when he knocked Anderson Silva silly with a big left hook and took his middleweight title, ending the longest title reign in UFC history at UFC 162.

On Nov. 16, Georges St-Pierre was the beneficiary of a controversial call, as he retained his welterweight title against Johny Hendricks via split decision. The aftermath of the evening included St-Pierre vacating his welterweight title after five and a half years and made a long-simmering debate about MMA's flawed scoring system finally explode.

Then on Dec. 28, what figures to be the biggest show of the year, UFC 168, ended in stunning fashion, as Silva suffered a gruesome leg injury throwing a kick at Weidman in the second round of their rematch. In the co-main event, Ronda Rousey solidified her position as the UFC's leading villain after refusing to shake Miesha Tate's hand after submitting Tate in the third round of their bantamweight title rematch.

After causing a chain of events which ended with the UFC facing 2014 without both of its biggest drawing cards, you could make a case for any of these three events taking home MMAFighting.com's 2013 Event of the Year award.

In the end, though, we're going with UFC 168. The year-end show had the strongest buzz of the three going into the evening. The allure of whether the UFC's greatest champion of all-time could regain his title trumped anything the other two main events could offer: UFC 162 and 167 were simply the latest title defenses by long-reigning champions. And 168 was the only card of the three with a co-main event, Ronda Rousey vs. Miesha Tate, which could have headlined a pay-per-view on its own. And while it was for all the wrong reasons, the shocking end to the main event placed the UFC front and center in the sports world's headlines for days to come.

That doesn't even bring into account the little here and there things which happened along the way, like Travis Browne proving himself a legit heavyweight contender with his vicious finish of former heavyweight champion Josh Barnett; a rejuvenating victory for Jim Miller, and Dustin Poirier's memorable finish of Diego Brandao, a day after Brandao both was way off on his weigh-in and threatened to stab Poirier.

Again, we could very well go 1A, 1B, and 1C with these events. But since we have to pick one, UFC 168 was the most significant card of the year, before, during and after. And as such, it gets the nod as the 2013 MMAFighting.com Event of the Year.

Runners-up:

1. UFC 167, Nov. 16, Las Vegas: In those moments between the final horn sounding on GSP-Hendricks and the reading of the scores, it seemed like we had the perfect end to a near-perfect evening: A new champion, to cap a night in which Robbie Lawler's redemption story continued with a win over Rory MacDonald; Tyron Woodley KO'd Josh Koscheck; and Donald Cerrone scored an exciting win over Evan Dunham. Then GSP was announced as the winner. Then he vaguely hinted at taking a break. Then came one of the most bizarre press conferences ever, as Dana White ripped into both GSP and the Nevada commission, before a battered St-Pierre showed up. Weeks later, St-Pierre vacated his title and announced a leave of absence. The ramifications of UFC 167 will be felt in the sport for a long time to come.

2. UFC 162, July 6, Las Vegas: Without UFC 162, the events of UFC 168 wouldn't have been possible. But UFC 162 didn't have the same level of anticipation going in as UFC 167 and 168 (in fact, some of the dimmer bulbs in the Twitterverse accused the UFC of forcing fighters to say Weidman stood a chance against Silva simply to drum up interest in the event). Then Weidman landed his history-making roundhouse, guaranteeing the rematch would be one of the most talked-about events in MMA history. This capped off an solid evening of action which included Frankie Edgar scoring a much-needed win over Charles Oliveira; Mark Munoz proving MMA wrestling doesn't have to be boring in his win over Tim Boetsch, and Cub Swanson's third-round rally to finish Dennis Siver in a key featherweight bout.

3. UFC 157, Anaheim, Calif., Feb. 23. UFC 157 transcended mixed martial arts and was a landmark even in the history of women's sports, period. The UFC may have taken too long to add women to the roster, but when they did, they went all out. There was no kid sister treatment, nor the sideshow element other combat sports promotions gave women's competitors. Rousey vs. Liz Carmouche, in both the first women's fight and title matchup, was the unquestioned draw at Anaheim's Honda Center. Rousey brought a rarely seen level of mainstream attention to the sport. Carmouche herself was a trailblazer, the first openly gay UFC fighter at the beginning of an unprecedented year for gay and lesbian visibility in pro sports. And, by the way, the card delivered, with Carmouche giving Rousey a battle for submitting to an armbar; the start of Urijah Faber's remarkable 4-0 year with a slick submission of Ivan Menjivar; and a fight of the year candidate on the undercard between Dennis Bermudez and Matt Grice.

4. UFC 166, Oct. 19, Houston. The fight cards listed up until this point all feature events which broke through to the mainstream, had moments which changed the course of the sport, and/or had historical significance. UFC 166, though, makes this list simply because it was one spectacular evening of fights. The opening two bouts had Kyoji Horiguchi and Andre Fili in outstanding UFC debut victories. The FS1 prelims featured a slugfest between Jessica Eye and Sarah Kaufmann (won by Eye via split decision), and Hector Lombard's brutal KO of Nate Marquardt in his welterweight debut. The main card delivered with smoking first-round knockouts by John Dodson and Gabriel Gonzaga; the Fight of the Year contender brawl between Gilbert Melendez and Diego Sanchez; and concluded with Cain Velasquez leaving no doubt in his trilogy fight with Junior dos Santos, finishing the game JDS in via fifth-round TKO.

5. invicta 5, Kansas City, April 5: A fight of the year contender in Michelle Waterson's sensational come-from-behind fourth-round submission win over Jessica Penne to win the atomweight title. The crowning of the first flyweight champ in Barb Honchak. A memorable slugfest in which Sarah Kaufmann decisioned Leslie Smith. The return of Cris Cyborg. And one of the submissions of the year in Rose Namajunas 12-second, flying armbar win over Kartina Cintron. If you missed Invicta 5, you missed one of the year's best events.

Honorable mentions: Bellator's debut card on Spike TV, Irvine, Calif., Jan. 17; UFC on FOX 7, San Jose, Calif. April 20; UFC Fight Night on FOX Sports 1 launch, Boston, Aug. 17; UFC 165, Toronto, Sept. 21.