The natural landmark created by the confluence of two rivers is referred to as a delta. Deltas form at river mouths where freshwater meets the ocean or sea and sediment is deposited, leading to rich, fertile areas. Notable examples include the Nile Delta in Egypt and the Ganges-Brahmaputra Delta in Bangladesh and India, both of which support extensive agriculture and dense populations. Deltas are crucial ecological zones, providing habitats for diverse wildlife and acting as important buffers against coastal erosion.