A woman holding a black and white photo mourns for her relatives died in the 1976 Tangshan earthquake in front of the memorial wall in Tangshan, North China's Hebei Province, July 28, 2013. Local residents came to the memorial park on Sunday to commemorate the 37th anniversary of the Tangshan earthquake. Photo: Xinhua

A man mourns for his relatives died in the 1976 Tangshan earthquake in front of the memorial wall in Tangshan, North China's Hebei Province, July 28, 2013. Local residents came to the memorial park on Sunday to commemorate the 37th anniversary of the Tangshan earthquake. Photo: Xinhua

A woman mourns for her relatives died in the 1976 Tangshan earthquake in front of the memorial wall in Tangshan, North China's Hebei Province, July 28, 2013. Local residents came to the memorial park on Sunday to commemorate the 37th anniversary of the Tangshan earthquake. Photo: Xinhua 

A man mourns for his relatives died in the 1976 Tangshan earthquake in front of the memorial wall in Tangshan, North China's Hebei Province, July 28, 2013. Local residents came to the memorial park on Sunday to commemorate the 37th anniversary of the Tangshan earthquake. Photo: Xinhua 

A man mourns for his relatives died in the 1976 Tangshan earthquake in front of the memorial wall in Tangshan, North China's Hebei Province, July 28, 2013. Local residents came to the memorial park on Sunday to commemorate the 37th anniversary of the Tangshan earthquake. Photo: Xinhua