Residents of Shanghai's Jiading District piece together a picture of Haibao, the Shanghai World Expo's mascot, on Saturday. Shanghai citizens held a series of activities to kick off the 2010 World Expo's 300-day countdown on July 5, 2009. [Xinhua]

Beijing and Shanghai are celebrating the kickoff of China's 300-day countdown to the 2010 World Expo in Shanghai on July 5 with a series of activities.

A large exhibition detailing the latest developments in expo preparations was unveiled in Beijing Sunday. The exhibit includes pictures of the pavilions set up by participating nations.

In Shanghai, Expo volunteers hosted a public campaign event aimed at helping the handicapped, called "We are By Your Side," on Sunday.

To date, more than 300,000 people have applied to be 2010 World Expo volunteers.

The 2010 World Expo in Shanghai is to be held from May 1 to October 31, 2010 and will include 239 participating nations and international organs.