The Triple Crown is one of the most sought-after achievements in horse racing. It is an elusive, almost impossible feat that jockeys, trainers and owners all dream of accomplishing.

The task of achieving the Triple Crown is monumental. A horse must win a series of three races -- the Kentucky Derby, Preakness Stakes and Belmont Stakes -- in just a five-week span, at three different race tracks, with three varying lengths. Factor in the fresh horses that race in the Preakness or the Belmont that skipped the Derby and the task becomes even more difficult.

The Triple Crown is a once-in-a-lifetime opportunity for a horse, as only 3-year-olds can run. Lose one race and the world must wait at least one more year to see history made.

Just 11 horses have claimed the coveted Triple Crown title, but none in recent history. The last horse to win was Affirmed back in 1978. This year, the winner of the Kentucky Derby, Orb will try to navigate his way into the Triple Crown record books.

It has been 34 years since the last Triple Crown winner, but the five horses below came devastatingly close:

2012: I'll Have Another

The world of horse racing crackled with excitement in the weeks leading up to the Belmont. I'll Have Another had won the first two jewels of the Triple Crown. He entered the Derby as an underdog with 15-1 odds, but pulled out a 1 1/2-length victory in front of record crowds. He then won the Preakness Stakes, pulling ahead by a neck to cross the finish line as the winner of the second leg.

His racing career came to an abrupt halt one day before the Belmont. He was scratched from the race and retired due to tendonitis.

2008: Big Brown

Big Brown entered the Derby as the 2-1 favorite, and bettors were rewarded as he became the first horse since 1929 to win from the 20th-post position. He won by 4 3/4 lengths over second-place filly Eight Belles, who was euthanized on the track.

At the Preakness, Big Brown once again claimed a decisive victory, winning by 5 1/4 lengths over Macho Again. Prior to the Belmont a crack was discovered on Big Brown's front left hoof. It was patched and he remained in the field for the Belmont, but the race was out of hand from the start and jockey Kent Desormeaux pulled him up. Big Brown became the first Triple Crown contender to fail to finish the race.

2004: Smarty Jones

In the 100th anniversary of the Triple Crown races, Smarty Jones came close to winning it all. He won the Kentucky Derby by 2 3/4 lengths and his trainer put his sights to the Preakness. Smarty Jones won the Preakness handily by a record of 11 1/2 lengths. The nation was in love with Smarty Jones, and he even appeared on the cover of Sports Illustrated that May.

Spectators packed the stands at the Belmont that year, setting an attendance record for the largest crowd at a sporting event in New York. He came in second behind longshot Birdstone. It was his only loss out of nine starts. His speed through the first mile and a quarter was blistering but the 1 1/2-mile distance, the longest of the three races, proved too much for Smarty Jones in the Belmont.

2003: Funny Cide

Funny Cide was the first gelding to win the Kentucky Derby since 1929. He beat favorite Empire Maker by 1 3/4 lengths. At the Preakness, he earned a 9 3/4-length victory, the second-largest margin in Preakness history. It seemed Funny Cide might have overexerted himself in the Preakness. He came in third in the Belmont to fresh horses Empire Maker and Ten Most Wanted, two horses that had skipped racing in the Preakness.

2002: War Emblem

War Emblem entered the Kentucky Derby as a longshot at 21-1 odds, but was victorious with jockey Victor Espinoza aboard. He then won the Preakness by three-fourths of a length over challenger Magic Weisner. All that was needed was a victory at the Belmont, but it was not to be. War Emblem stumbled out of the gate and never got in rhythm. He took a brief lead in the final turn but waned in the home stretch, and he lost to Sarava, who had record odds of 70-1. War Emblem finished eighth.