Cambodian Prime Minister Hun Sen (front) shows his respect to an ancient stone sculpture returened from the Metropolitan Museum of Art before the opening ceremony of the 37th session of the World Heritage Committee (WHC) in Phnom Penh, capital of Cambodia, on June 16, 2013. The 37th session of WHC kicked off on Sunday evening here and would last until June 27 in order to consider inscribing 31 new sites onto the UNESCO's World Heritage list. [Photo/Xinhua]