predecessor to modern Lake Titicaca (Titicaca, Lake), on the Bolivia-Peru border during the Pleistocene Epoch (approximately 1.8 million to 11,800 years ago). Its surface is thought to have been at least 100 metres (330 feet) higher than Lake Titicaca's current level. As the lake drained, it formed two smaller lakes: Titicaca, in the northern portion of its basin, and Minchin, predecessor to modern Lake Poopó (Poopó, Lake), in the southern basin.