On the 150th anniversary of the sacking of Beijing's famed Imperial Garden, 70-year-old historian Young-tsu Wong reckons the feelings of grief mixed with desolation that once hung over the place are gone.

On Monday, Wong, visiting the park 29 years after his first tour, said the Old Summer Palace, known as Yuanmingyuan in Chinese, is a delight.

"The history of Yuanmingyuan over the past 150 years is a reflection of China's ups and downs over the same period," said Wong, a professor of history at Virginia Poly Institute and State University and author of "A Paradise Lost - The Imperial Garden Yuanmingyuan."

The imperial garden, an architectural wonder of its age, was built in the 18th and 19th centuries during the Qing dynasty (1636-1911). British and French forces destroyed the place on Oct. 18 and 19, 1860, during the Second Opium War, a move to force China to open its market.

Walking through the gardens, Wong said the 150th anniversary of the sacking is a chance for Chinese, as well as British and French, to reflect on the incident and its significance.

Wong and French historian and journalist Bernard Brizay - author of "The Sack of the Summer Palace (Le Sac du Palais d'Ete)" - chatted in the garden Monday in front of the ruins of the Symmetric and Amazing Pleasure fountain complex (Xieqiqu in Chinese), which the French army robbed and the British forces set ablaze.

The dialogue between the 70-year-old Chinese historian and the 69-year-old French historian was hosted by the Foreign Language Teaching and Research Press, the publisher of Wong's book.

"I was moved deeply when I first came to Yuanmingyuan in 1981. The history grabbed me with grief and sorrow," Wong said.

Once an imperial garden, today Yuanmingyuan is open to the public as a park. It is located near China's two most prestigious universities - Tsinghua University and Peking University - and Zhongguancun, known as "China's Silicon Valley."

Brizay said French people felt guilty about Yuanmingyuan's destruction and would like to apologize, like the famous French writer Victor Hugo (1802-1880) did.

Brizay attended the unveiling ceremony of a bronze statue of Victor Hugo in the Old Summer palace Saturday.

Hugo criticized the destruction of Yuanmingyuan in his "Expedition de Chine (Expedition to China)," in which he likened the looting to "two robbers breaking into a museum, devastating, looting and burning, leaving laughing hand-in-hand with their bags full of treasures; one of the robbers is called France and the other Britain."

In his letter, Hugo hoped that one day France would feel guilty and return what it had plundered.

"I felt sad when I came to Yuanmingyuan, which is not only a beautiful imperial garden, but also a national library like the La Bibliotheque Nationale de France (the National Library of France) and a museum like the Louvre," Brizay told Xinhua.

Brizay believes the destruction must be remembered to avoid another tragedy. "Nothing like this should happen again," he said.

He also believes it is time for the Chinese people to forgive. "We must look forward, but not behind."

"Both historians are trying to be impartial and objective, after one and a half centuries. Calmness is the gift of time," said Chen Mingjie, the vice secretary general of the Yuanmingyuan Society and a director of the Yuanmingyuan Administration.

Chen said Yuanmingyuan should be a place of commemoration to remind Chinese people of the days when China was backward, so they can learn from history.

"Commemorating at this time is like wiping out the disgrace, as the Chinese people have stood up after 150 years," Chen said.

The destruction of Yuanmingyuan had a strong impact on the Chinese people. It was a turning point in Chinese modern history as it triggered the Qing government's "Self-Strengthening Movement" (1861-1895), a period of institutional reforms initiated after a series of military defeats and concessions to foreign powers, he said.

During the movement, modern science and technology were introduced into China and the Qing's Northern Fleet was established to fight foreign forces, he said.

His view was echoed by Ye Tingfang, historian and researcher of Institute of Foreign Literature of Chinese Academy of Social Sciences.

"The destruction of Yuanmingyuan not only affected the declining Qing authorities, but also awakened the ordinary people, who realized how unenlightened and blind the country was and began to think and reform," Ye said.

Zhang Ming, an historian at Renmin University in Beijing, said the destruction was not the most insulting event in China's history as it was followed by the Second Opium War, but it was still an insult and a sorrow.

"However, history is moving on. The guns and ships of foreign powers will never enter China's territory again, and the boots of soldiers will no longer trample China's lands. Today, the newcomers from the Western countries are investors, tourists and students," Zhang said.

Today's Western people preferred to forget that part of history while Chinese people were inclined to remember, said Zhang. "History is not a heavy burden for the invaded country, nor for the invaders. History should not be the seed of hatred," he said.

"The commemoration should be peaceful and only peace can lead humankind to a better future. Only knowing that truth, can later generations of the invaders and the invaded sit together to commemorate the miserable past," Zhang wrote in his blog.

Activities commemorating the destruction have been held since September, including exhibitions of cultural relics and old photographs and paintings, he said.

A grand reception was held Monday evening in front of Dashuifa (Great Fountains), the palace's biggest attraction.

The Yuanmingyuan Society hopes to have Yuanmingyuan recognized as a "harmonious commemoration for all."

"Yuanmingyuan is not only a treasure for the Chinese people. It is also a treasure for the world," Chen Mingjie said.

"The garden was built as a complex of architectural styles from around the world, a symbol of inclusiveness. Today, at this place, we hope to welcome all guests and cultures, just like today's China."

The destruction of Yuanmingyuan was an attack on the Chinese people, but it was not painful enough to alert the country to events elsewhere in the world at the time, said a commentary by fiction writer Xiaohan on Sina.com.

Three months before the attack, the famous debate between Charles Darwin (1809-1882), writer of "The Origin of Species," and the church began in London, after which, evolution theory spread to most Western countries, Xiaohan wrote.

The same year, Emperor Napoleon III of France allowed freedom of the Press, and allowed the senate and the legislative delegation to discuss his affairs and the media to publish debates in the National Assembly.

France and the United Kingdom also signed a trade agreement, which brought competition from foreign countries.

It was time to really self-reflect and to think about the true reasons for the tragedies, he said.

"When English physicist, astronomer and mathematician James Hopwood Jeans (1877-1946) found the carbon atoms of living things have different characteristics from others, what were we doing? Sure we can say that we developed slower than Western countries because we were invaded by foreign powers, but that was not the only thing," he wrote.