Macaronesia (Portuguese: Macaronésia) is a collection of four volcanic archipelagos in the North Atlantic Ocean, off the coasts of the continents of Europe and Africa. Each archipelago is made up of a number of Atlantic oceanic islands, which are formed by seamounts on the ocean floor and have peaks above the ocean's surface. Some of the Macaronesian islands belong to Portugal, some belong to Spain, and the rest belong to Cape Verde. Politically, the islands belonging to Portugal and Spain are part of the European Union. Geologically, Macaronesia is part of the African tectonic plate. Some of its islands – the Azores – are situated along the edge of that plate at the point where it abuts the Eurasian and North American plates.