Many centuries ago on the border of Belize and Guatemala, Maya people built a large city surrounded by a cultivated jungle garden that was home to around 20,000 people, which archaeologists call El Pilar. They had large structures, including palaces and pyramids, and paved their plazas in lime plaster to divert rainwater into reservoirs. Archaeologists using lasers from the air have recently identified a fortress-like structure nearby covered by vegetation.