These American war heroes were overlooked for decades due to race discrimination. Here are their remarkable Medal of Honor stories.

• On March 18, 2014, President Barack Obama awarded 24 Army veterans with Medals of Honor in a single ceremony.
• The unusual event honored veterans of World War II, the Vietnam War, and the Korean War who had previously been overlooked for the nation's highest military award for valor.
• A 12-year congressional review of service records found dozens of awards had been overlooked or denied due to racial or ethnic discrimination.
• Obama awarded 21 medals posthumously, and three to living recipients Melvin Morris, Jose Rodela, and Santiago Erevia.

On March 18, 2014, in one of the longest ceremonies of its kind, 24 Army veterans received the Medal of Honor for actions during their service in World War II, the Korean War, and the Vietnam War.

12 years earlier, Congress began a review of Jewish and Hispanic Americans' war records, finding that dozens had been overlooked or denied the nation's highest military award for valor due to discrimination. 

"No nation is perfect," President Obama said at the ceremony. "But here in America, we confront our imperfections and face a sometimes painful past, including the truth that some of these soldiers fought and died for a country that did not always see them as equal."

Three living veterans were honored at the ceremony, and 21 were honored posthumously for their heroic actions. These are their stories.

SEE ALSO: These are the incredible stories of US troops who've earned the Medal of Honor during the war on terror

Spc. 4th Class Leonard Alvarado sacrificed his own life in the dense jungles of Vietnam: 'His actions in the face of the enemy were always extraordinary.'

With nothing but his M60 machine gun, Spc. Alvarado faced barrages of enemy gunfire, grenades, and satchel charges to provide cover as his unit aided another platoon in the jungles of Phuoc Long Province, Vietnam. 

Steve Koppenhoefer, Alvarado's platoon leader, told Stars and Stripes the specialist was an extraordinary yet intimidating figure on the battlefield. He died from wounds sustained during the battle and was originally awarded the Distinguished Service Cross, the Army's second-highest award for bravery in combat.

Alvarado's award was upgraded to the Medal of Honor to reflect his sacrifice. Read the full citation.

Cpl. Joe Baldonado drew enemy fire towards his own position to protect his comrades.

Cpl. Baldonado stayed in an exposed position for some three hours to defend his platoon from waves of enemy attacks near Kangdong, Korea. 

3rd Squad, 2nd Platoon, Company B, 187th Airbone Infantry Regiment was ordered to defend Hill 171 against enemy efforts to take control of their position. Attacking forces concentrated their fire on Baldonado's position, eventually retreating. 

Baldonado was killed by a grenade that exploded near his position. To date, his remains have not been recovered.

Read the full award citation. 

5-foot-3 Pvt. Pedro Cano crawled with a rocket launcher through heavily mined areas to confront German soldiers — and somehow survived the ordeal.

Between December 2 and 3, 1944, Pvt. Pedro Cano killed nearly 30 enemy soldiers near Schevenhutte, Germany. 

Cano crawled through a mined area with a rocket launcher, firing rockets and tossing grenades into enemy positions as close as 10 yards away. The next day, he crawled through heavy enemy fire, again destroying numerous enemy positions. 

Cano, born in Mexico in 1920, became a US citizen in 1946. 

Read the full citation.