He won the gold medal at the 2004 Olympics in the 110m Hurdles, but has since struggled with problems with his Achilles tendon. It led him to drop out of the 2008 Olympics moments before he was set to compete.
But he worked to get back for London, and this morning he was ready to compete in the event he had once dominated the world in. It was clear before the race that this moment was special for him.
Then the race started.
Liu's Achilles, the same injury that had robbed him of the 2008 games, had been aggravated again.
You could see the frustration on Liu's face.
He struggled to even get up.
Finally Liu did get up. He hopped toward the tunnel, ignoring the offered wheel chair.
It looked like London would end as another bitter disappointment for the once great runner.
But then, he stopped.
And he turned around.
And he re-entered the track to a stadium-shaking ovation, and finished the 110 metres.
Stopping first to kiss the final hurdle.
As soon as Liu crossed the finish line, his fellow athletes embraced him.
And helped him.
And just like that Liu Xiang's tragic day became what is sure to be one of the enduring images of the 2012 London Olympics.