Preah Vihear Temple
In 1907, the Thai-Cambodian border was mapped by the French on behalf of a bilateral border commission. According to the 1904 agreement, the border would follow the natural watershed between the countries. However, the resulting map deviated by showing Preah Vihear Temple as being in Cambodia, even though it is on the Thai side of the watershed. Thailand accepted the map for official use. The Thais discovered the error when they made their own survey in the 1930s, but the ICJ ruled that they had waited too long to protest and lost the temple by "acquiescence".