The Shanghai World Expo is to formally open its door to the highly avid public Saturday morning after a commencement ceremony at the Expo Center.

Hundreds of thousands visitors, from both at home and abroad, are thronging to the gates of the Expo park, waiting for security checks in long queues.

Around 300,000 tickets have been sold or distributed for this opening day, organizers said.

The Shanghai World Expo, with a theme of "Better City, Better Life", is to run until Oct. 31 and expected to draw 70 million visitors from both China and abroad.