ar, politics, climate change…whatever the reason, civilisations rise and fall. Some nation states vanish from maps, only to be reborn with new names and new borders, as happened when the Soviet Union dissolved into 15 independent nations in 1991 or when Yugoslavia broke up in the early 1990s (). Some countries are). Some, like the Khmer Empire, vanish suddenly, leaving behind tantalising structures for archaeologists to ponder on.
