With the "Flame of Hope" burning bright against the blue Athenian until July 4, the 13th Special Olympics bring together 7,500 athletes from 183 countries across the globe who will compete in 22 Olympics-type sports.
With the Special Olympics athletes are 2,500 coaches, 40,000 family members and 3,000 media representatives, as well as 25,000 volunteers.
Greece's President Karolos Papoulias declared the opening of the Special Olympics after the parade of athletes and members of the national delegations into the Stadium.
"They say that there are no heroes in our era. Just a few minutes ago, 7,500 real heroes paraded before us, 7,500 real winners," Athens Special Olympics Organising Committee president Joanna Despotopoulou told the gathered spectators.
"I think we're home," Dr. Timothy Shriver, chairman and CEO of Special Olympics told an enthusiastic crowd.
"Let me extend my thanks to the people of Greece," he said. "Despite all the difficulties and challenges this country is facing, Greece did not fail us, and the athletes of Special Olympics will not fail Greece".
A highlight of the event was a performance of legendary singer, songwriter and musician Stevie Wonder, who opened with his song "You can feel it" followed by "You are the sunshine of my life". Wonder also performed a duet of "That's what friends are for" with long-time Special Olympics supporter and recording artist Vanessa Williams, who co-hosted the show with noted Greek tenor Mario Frangoulis.
The opening ceremony also featured a rendition of Homer's "Odyssey", and performances by popular Greek singer Alkistis Protopsalti with Italian tenor Vittorio Grigolo, and special presentations by actresses Zhang Ziyi and Maria Menounos.
After President Papoulias officially declared the Games opened, the Special Olympics flag was carried into the stadium by Pyrros Dimas, Nadia Comaneci, Edwin Moses, Michelle Kwan, Jermaine Edie, Ana Milivojevic and Ana Eduarda.
Members of the Greek and US Special Olympics teams led the athletes in the Special Olympics oath:
"Let me Win!
But if I Cannot win,
Let me be Brave in the Attempt!"
Finally, the Flame of Hope was run through the stadium to light up the Torch marking the start of the Games.