The world's tallest bridge opened to traffic on Sunday morning in Guizhou province, slashing travel time across a deep canyon from two hours to just two minutes after three years of construction.

The Huajiang Grand Canyon Bridge, soaring 625 metres above the Beipan River in Guizhou's mountainous terrain, is nearly nine times as tall as San Francisco's Golden Gate Bridge.

With a main span of 1,420 metres, the project has become the world's longest-span steel truss girder suspension bridge in mountainous terrain, according to Guizhou provincial authorities.

Spanning the Huajiang Grand Canyon, dubbed "the Earth's crack," the 2,890-metre-long structure is the latest addition to the rapidly expanding infrastructure network of the world's second-largest economy.

The former world's tallest bridge, which spans the Beipan River, is located just over 100km from the Huajiang Grand Canyon Bridge. The previous record-holder, opened in 2016, has a vertical clearance of 565.4 metres from the bridge deck to the river surface below.

Over the years, Guizhou, one of China's least developed provinces, has constructed over 30,000 bridges in its mountainous terrain, including three of the world's tallest. The province is home to nearly half of the world's 100 tallest bridges. (Xinhua)