WOW!!...Highest and longest glass bridge opens over China's Zhangjiajie Grand Canyon

China just added a bunch of new claims to its planet-beating achievements -- this time its the world's sweatiest palms, the trembliest knees and the most-flipped stomachs.

Oh yes -- and the world's highest and longest glass-bottomed bridge.

Thousands of visitors have been steeling themselves to walk across the newly opened structure that spans the Zhangjiajie Grand Canyon in Hunan Province.

The six-meter wide bridge stretches 430 meters over a 300-meter-deep valley between two cliffs in the beautiful Zhangjiajie Park, said to have inspired the scenery for the sci-fi movie "Avatar."

The bridge's builders say its toughened glass panels can support hundreds of people at a time. They've staged safety demonstrations inviting people to try to smash the glass.

Photos: China opens world's longest and highest glass bridge

Safety first – The bridge's builders say its toughened glass panels can support hundreds of people at a time. They've staged safety demonstrations inviting people to try to smash the glass.

Designed by Israeli architect Haim Dotan, the glass-bottomed bridge will also feature the world's highest bungee jump and serve as a runway for fashion shows.

Visitors have been reportedly lining up for hours to cross the bridge, but although it can take 800 people at a time, access is being restricted to a maximum 8,000 a day.

Authorities have been working hard to stress the bridge's safety credentials, inviting journalists to try to smash their way through its thickened glass.

In another demonstration, a car was driven over the structure.

Scary incident

There's a reason folks might be wary.

In an incident in October last year, cracks appeared in a mountainside glass walkway in Yuntaishan Scenic Park, in China's central Henan province, just two weeks after opening.

Visitors were sent running and screaming in panic, according to witnesses, although park officials said the damage was superficial and did not pose any danger.

The Zhangjiajie bridge is one of many new glass-bottomed tourist attractions that have been drawing crowds in China and around the world.

Also in Zhangjiajie, a 100-meter-long glass skywalk, stretching around a cliff on the park's Tianmen Mountain, opened in August.