A ceremony was held in Chongqing Monday to mark the completion of China's first underwater museum, built in the Three Gorges Dam area.

Photo taken shows an exhibition room on land. A ceremony was held in Chongqing Monday to mark the completion of China's first underwater museum, built in the Three Gorges Dam area.

The Baiheliang Museum, which cost 189 million yuan (US$27.6 million), was built about 40 meters below surface in the upper reaches of the Yangtze River off the coast of Fuling City, Chongqing Municipality. The structure protects a reef created about 1,200 years ago to measure the changes in water levels.

The complex consists of the museum, a connecting passageway, an underwater anti-collision pier and an exhibition room on land.

Construction of the main part of the museum was completed in 2006, before the dam raised the water level in 2008.

Baiheliang, literally "White Crane Ridge", is a 1,600-meter-long and 25 meter-wide smooth stone ridge engraved with inscriptions about China's longest river, dating from 763 in the Tang Dynasty to the early 20th century.

On the huge rock are 20 fish sculptures that serve as water-level markers and about 30,000 characters of Chinese poems from different dynasties.

It is claimed to be the world's oldest hydrographic survey device and is one of the four state-level national treasures in the Three Gorges area.

The museum is expected to open to tourists Wednesday. Visitors may observe the reef through a video camera on the land, windows on the underwater corridor, or they may simply dive into the water.