The Saint Peter and Saint Paul Archipelago (Portuguese: Arquipélago de São Pedro e São Paulo) is a group of 15 small islets and rocks in the central equatorial Atlantic Ocean. It lies in the Intertropical Convergence Zone, a region of severe storms. It is approximately 510 nmi (940 km; 590 mi) from the Brazilian northeastern coastal town of Touros, 625 km (388 mi) northeast of the archipelago of Fernando de Noronha, 990 km (620 mi) from the city of Natal, and 1,824 km (1,133 mi) from the western African coast. The islets expose serpentinized abyssal mantle peridotite and kaersutite-bearing ultramafic mylonite on the top of the second-largest megamullion in the world (after the Parece Vela megamullion under Okinotorishima in the Pacific) and the highest one of the world. It is the only location on Atlantic Ocean where the abyssal mantle is exposed above sea level. In 1986, the archipelago was designated as an environmentally protected area. Since 1998, the Brazilian Navy has maintained a permanently manned research facility on the islands. The main economic activity around the islets is tuna fishing.