Thousands of runners followed a course around Olympic venues
With 100 days remaining until the Olympic Games get under way, Chinese authorities are marking the milestone with a series of celebratory events.
Ten thousand Beijing residents took part in a fun-run and later in the day an Olympic theme tune will be unveiled.
Wednesday also saw the return of the Olympic flame to China after its protest-hit global relay.
It arrived in Hong Kong, where officials have already deported seven activists ahead of Friday's parade.
Three pro-Tibet protesters were deported on arrival on Tuesday, as was a writer scheduled to address an event on media freedom. Three Danish rights activists were deported earlier in the week.
The Olympic flame arrives in Hong Kong
The torch has been taken to an undisclosed location ahead of Friday's parade, where demonstrations are expected.
Meanwhile, a second Olympic torch is being readied by a group of climbers for an attempt on Everest.
In Beijing, meanwhile, thousands of residents turned out to participate in a mini-marathon around Olympic venues to celebrate the 100-day mark.
Later an Olympic theme tune, Beijing Huanying Ni - Beijing welcomes you, will be unveiled in the Forbidden City by 100 singers and celebrities, including actors Jackie Chan and Andy Lau.
While unrest in Tibet and the Olympic flame's troubled journey have made headlines around the world, Beijing's preparations for the Games have received less attention.
Some Olympic venues have been completed ahead of schedule and the city has spent nearly $40bn (£20bn) on improved infrastructure, including a new airport terminal and underground rail lines.
In a statement, the IOC said the Beijing Organising Committee had "put a tremendous amount of effort into putting on great Games for the athletes".
"It is currently fine-tuning its operations and we are satisfied by the assurances that we have received across a number of areas of Games preparations, ranging from media service levels to environmental contingency plans for improved air quality."
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