Remains of Garden Gate in 1870. [Photo provided to China Daily]

Earlier this year Guo announced at Tsinghua University that her team had completed the research and development of a prog program called Digital Yuanmingyuan. More than 80 people spent 15 years on improving protection of the cultural heritage of the Old Summer Palace, drawing on more than 10,000 archives, completing 4,000 design drawings of the architecture, and making 2,000 digital models of the buildings.

Guo has been doing research on the Old Summer Palace for many years. In 1960 she graduated from Tsinghua University. Before her lay a career building houses, but she was instead assigned to teach and study ancient architecture and gardens at Tsinghua University.

She then started visiting and revisiting the Old Summer Palace. Farmers nearby had converted sections of it into farmland. In the overgrown weeds and farmland Guo searched for the remnants of hills and water systems, bridges, artificial hills, stones, building foundations and stone carvings, which were scattered among houses, pig pens and woods and on the banks of rivers and lakes.

At the end of the 1980s Guo headed a team that was designing a tourist park based on the Old Summer Palace in Zhuhai, Guangdong province. She chose 18 of the 40 viewing places, which Emperor Qianlong's artists had painted in great detail, and rebuilt them in the 580,000-square-meter park.

It opened to the public during the Spring Festival of 1997, and on March 8 that year, about 80,000 people visited it. But Guo always felt that, the park could never be regarded as representing the cultural essence of the Old Summer Palace.