Intense nationalism and disputed history — and maps — stoke the neighbors’ hostilities. Even a surge of international diplomacy has brought little hope of a lasting peace.

Cambodia and Thailand agreed to an "immediate and unconditional" ceasefire Monday after five days of intense fighting along their shared border. The ceasefire, negotiated in Malaysia with involvement from the U.S. and China, took effect at midnight.

The leaders of Cambodia and Thailand agreed to a ceasefire in a bid to bring an end to their deadliest conflict in more than a decade.