For 21 WrestleMania events, he was untouchable. Many men stepped up to the plate, but no one could defeat The Undertaker. He continued to prove to everyone that he was The Phenom of the WWE. Whether he was in the main event, or on the midcard, The Undertaker gave fans a show and emerged as the winner at the "granddaddy of them all."

Then came WrestleMania XXX. An aging Undertaker would be faced with his biggest challenge to date; squaring off against the former WWE and UFC Champion, Brock Lesnar. Going into the match, fans were used to the build up that has you believing that his opponent could beat him and in the end, he finds a way to win the match. Prior to WrestleMania, it was indicated that three things in life were guaranteed, taxes, death, and The Undertaker’s undefeated streak. His die-hard fans, once known as the "creatures of the night," did not believe that The Deadman would be defeated. But at WrestleMania XXX, the outcome was different. The entire Superdome was left in shock when The Beast conquered The Undertaker’s undefeated streak at WrestleMania. The Undertaker was now 21-1.

Many thought that would be the end of The Undertaker. However, he would return to the winning side the following year. For weeks, the "new face of fear," Bray Wyatt called him out. With The Undertaker losing at WrestleMania XXX, it was believable that he may actually lose for the second year in a row. But fortunately for The Undertaker, he was able to defeat Bray Wyatt. The Undertaker is clearly in the twilight of his career, but he will always be linked with WrestleMania. Here are the top 12 things fans need to know about The Deadman and the biggest spectacle in sports entertainment.

12 12. Concussion at WrestleMania XXX

In The Undertaker’s match with Brock Lesnar, many people expected there to be a dogfight throughout. However, the match seemed to drag after the seven-minute mark and it didn't seem like your normal Undertaker match. Considering that he and Lesnar had history from the early 2000s, not to mention their face-to-face confrontation at UFC, this did not seem like a match that had been brewing for ages. Instead, it seemed lackluster until the final minutes. Lesnar would win the match and then as The Undertaker retrieved to the back, he passed out. The Undertaker was rushed to hospital where he spent the night concussed. explaining the pace of the match.

11 11. Used the Johnny Cash Song, “Aint No Grave.” For An Entrance

At WrestleMania XXVII, The Undertaker faced Triple H. This was a No Holds Barred match where the two legends collided. This theme was fitting considered The Undertaker won the match, but had to be carried out. He would eventually rise to face the Triple H following year at WrestleMania XXVIII. The WWE has dubbed The Undertaker’s current theme over the Johnny Cash song in all replays.

10 10. Wrestled Triple H Three Times

When The Undertaker faced Triple H at WrestleMania XXVII, many fans were annoyed by the fact that the WWE did not acknowledge the fact that they faced each other 10 years prior at WrestleMania X-Seven. Even though their first matchup was not a No Holds Barred match, it might as well have been considering they beat each other all over Reliant Stadium. The Undertaker was victorious at both X-Seven and XXVII, but since he was laid out after the latter, The Deadman demanded a rematch because he did not want the lasting image to be him getting carried out of Atlanta. He would get his rematch with Triple H, this time in a Hell in a Cell match. Despite Triple H’s best friend Shawn Michaels, being the special guest referee, The Undertaker emerged victorious and his undefeated streak at WrestleMania remained.

9 9. Missed Two WrestleMania Events

The Undertaker has been a staple at WrestleMania. However, he missed two due to injury. In 1994, he missed WrestleMania X after being defeated by then WWE Champion Yokozuna at the Royal Rumble. The storyline was that Yokozuna, with help, had finally beaten The Undertaker and buried him. Many may remember the imfamous, “I will not rest in peace” promo from the casket after the match. He missed WrestleMania 2000 also, but would later come back with a new identity: Biker Taker.

8 8. Tag Match Turned Handicap Match

At WrestleMania XIX, The Undertaker was booked to team with Nathan Jones to face Big Show and A-Train. However, Big Show and A-Train attacked Jones, leading Undertaker to face the two monsters in a Handicap match. The odds looked stack against him but considering he was The Undertaker, would emerge as victorious in this two-on-one WrestleMania bour.

It's been rumored that WWE realized that Nathan Jones was too green and removed him from the match at the last second.

7 7. Kid Rock Theme

When The Undertaker made his return in 2000, he used the Kid Rock song, "American Bad Ass." That would be the persona he would embrace for the next two years, however, he never used that song at WrestleMania. It was soon replaced with Limp Bizkit’s “Rollin'.”  Considering how the whole American Bad Ass gimmick fit entirely well with the theme song, an epic motorcycle ride down the long WrestleMania entrance ramp with the Kid Rock song on full-blast would have been quite a sight.

6 6. Never Won a Title with Paul Bearer by His Side

Paul Bearer served as The Undertaker’s manager for majority of his career. Paul Bearer turned on The Undertaker in 1996 and joined forces with Mankind. He would later introduce the world to Kane n 1997, who was The Undertaker’s opponent at WrestleMania XIV. The Undertaker won the WWE Championship and World Heavyweight Champion at 13, 23, and XXIV, but not one time was Paul Bearer by his side.

5 5. One of Two Wrestlers to Win Both World Titles at WrestleMania

AFter Vince McMahon purchased WCW in 2001, the company had two major championships until the unification in 2013. Without the titles being unified, The Undertaker and John Cena are the only two Superstars to win both the WWE Championship and the World Heavyweight Championship at WrestleMania. Two of McMahon's greatest go-to WrestleMania attractions have formed a rather unique WrestleMania club.

4 4. Involved in All Hell in a Cell Matches at WrestleMania

The Undertaker will face Shane McMahon at WrestleMania in a Hell in a Cell match at WrestleMania 32. The match debuted with him and Shawn Michaels squaring off at Bad Blood 1997. His most iconic moment in the Cell actually occurred on top of it when he threw Mankind off the top through the ring announce tables. The Cell will make only its third appearance at WrestleMania 32. Both of the previous matches (XV and XXVIII) featured the man who made it famous, The Undertaker.

3 3. Never Wrestled the Four Biggest Crossover Stars

Hulk Hogan, Stone Cold Steve Austin, The Rock, and John Cena arguably have the most crossover appeal in WWE history. While The Undertaker defeated Hogan for his first WWE Championship and had epic matches with Austin, Rock, and Cena, he has never faced any of these men on the biggest stage of them all. These are four dream matches which have never occurred with the only true possibility remaining being an Undertaker/Cena match coming next year.

2 2. WrestleMania X8: The Streak Acknowledged

At WrestleMania X-Seven, Jim Ross acknowledged the fact that The Undertaker was undefeated at WrestleMania after he defeated Triple H. However, it was not until after Big Evil (as he was known as in 2002) defeated Ric Flair that he held up his fingers and signaled to everyone that he was 10-0 at WrestleMania. As we all know, 11 more victories would follow this win over Ric Flair before The Streak was finally put to rest.

1 1. For and Against Vince McMahon

At WrestleMania 32, The Undertaker has the task of protecting Monday Night Raw from his opponent Shane McMahon. After taking time off to venture into other businesses, Shane decided that he did not like the way things were being run at the WWE and decided that he wanted to protect its legacy. He and his father, Vince McMahon, made an agreement, if Shane defeats The Undertaker in a Hell in a Cell match, then he would have control of Monday Night Raw.

At WrestleMania XV, The Undertaker faced The Big Boss Man in a Hell in a Cell match. Boss Man was defending the honor of Vince McMahon. The Undertaker had terrorized the McMahon family claiming to answer to a "higher power." Now when everything was revealed, it Vince McMahon was actually the "higher power" and the plan was to take out Stone Cold Steve Austin. Nonetheless, on the surface The Undertaker was against McMahon that night in Philadelphia, meaning he's fought for and against Vince.