Shrouded in scaffolding as scores of workers overhaul the tallest hall in China's Forbidden City, renovation of the most significant hall in the country is well under way.

The renovation is expected to restore the hall's former glory from the Qing Dynasty (1644-1911), said Jin Hongkui, the palace's deputy curator.

The renovation includes repairing the roof sides which have already started sinking, repairing corrupted wood columns, changing the broken glass tiles and repainting the ceramic glaze of the tiles.

The Hall of Supreme Harmony, China's tallest timber ancient palace building, was closed to the public in January. Workers are overhauling the outer and inner frame of the hall and the renovation plan will be discussed by experts in June, Jin said. The whole renovation will last for two years.

Located at a significant place at the axis of the Forbidden City, the Hall of Harmony used to be the place where grand ceremonies were held such as the emperor's enthronement, wedding, birthday and important occasions like the Chinese Lunar New Year.

The hall, originally completed in 1420, was rebuilt after several fires and is over 300 years old.

Examination and planning work for the hall's renovation began in 2004, according to Jin, which included literature research and collecting. Professionals combined manual mapping, three-dimensional laser scanning and wood survey technologies to overhaul and analyze the status of the hall.

Experts from the Italian cultural heritage department also contributed to the work of pollutant analysis and tested repairing materials, bringing their experience of renovating ancient architecture in Europe, Jin said.

He said the main structure of the hall is basically stable. But parts of the wood frame, ornaments, walls, roof tiles and the unique brackets inserted on the top of columns have suffered damage.

The paintings on the outer eaves did not comply with the original design during the past renovations, he added.

The Forbidden City, now known as the Palace Museum, situated in central Beijing, was the power center of the Ming (1368-1644) and Qing (1644-1911) dynasties from 1420 to 1912.

The labyrinthine complex, home to 24 emperors, their families and courtesans, and reputed to have 9,999 rooms, is one of China's best known icons and most popular tourist attractions. It is visited by 7 million to 8 million tourists every year.

UNESCO listed the Forbidden City as a World Cultural Heritage Site in 1987.

The renovation of the Palace Museum, which started in 2002, will take more than 10 years to complete at a cost of over 2 billion yuan (250 million U.S. dollars).

By the end of 2005, about 38,000 square meters of ancient architecture were repaired, costing more than 200 million yuan (25 million U.S. dollars).

Editor: Wing