UNESCO decided Saturday to add 12 sites in southwestern Japan that are linked to the history of the country's persecuted Christians to the World Heritage list.

The sites include the Oura Cathedral in Nagasaki, the oldest surviving church in the country and which is already designated as a national treasure; the remains of Hara Castle, a site of the Shimabara-Amakusa Rebellion that led to establishment of a national policy of seclusion; and the beginning of the hidden Christians' unique system to transmit their faith and beliefs by themselves.

The sites were among 28 World Heritage candidates reviewed by the U.N.'s World Heritage Committee for four days through Monday in Bahrain.