Vast numbers of Chinese relics have been looted during the past 200 years & are mainly in the hands of private foreign collectors. China is now trying to draw attention to this issue for their own citizens, by releasing a set of stamps featuring some of the most prominent pieces of artwork that they feel ought to be returned.
China Radio International 
Stamps Encourage Return of Relics
National Philatelic Corporation issued stamps featuring the heads of stolen bronze animals from Yuanmingyuan.
In a bid to promote efforts to retrieve Chinese relics overseas, the China National Philatelic Corporation issued a set of stamps this week featuring the heads of 12 stolen bronze animals from Yuanmingyuan Garden.
Each set consists of 12 stamps featuring bronze heads of 12 sculptures formerly guarding a mansion in Yuanmingyuan in northwest Beijing. The sculptures have animal heads and human bodies.
Yuanmingyuan was looted and burned down by Anglo-French Allied forces in 1860, and the heads were removed by the intruding foreign troops.
Four bronze heads — the cow head, tiger head, monkey head and pig head — have been recovered, and those stamps bear their photograghs. But stamps of the other eight heads use artists’ renderings as the heads themselves remain missing overseas.
“Hopefully, it will remind people that we need to work harder to retrieve our historical treasures,” said Zhang Yongnian, director of China’s Lost Cultural Relics Recovery Fund, a non-governmental organization set up to retrieve Chinese relics overseas.
Between 300,000 and 600,000 Chinese cultural relics are housed in more than 2,000 museums in 47 countries worldwide, accounting for just 10 percent of all lost Chinese priceless cultural treasures. Most of the lost treasures are owned by private collectors.