The expedition of Juan Bautista Pastene makes landfall in San Pedro Bay, southern Chile, claiming the territory for Spain.

Giovanni Battista Pastene (1507–1580) was a Genoese maritime explorer who, while in the service of the Spanish crown, explored the coasts of Panama, Colombia, Ecuador, Peru and Chile as far south as the archipelago of Chiloé.

San Pedro Bay is a bay in southern Chile located in the southern coast of Osorno Province. In 1965 the ships Janequeo and Leucoton sank in the bay. The bay has the form of a half-circle open to the west and has several small coves.

Zona Sur is one of the five natural regions on which CORFO divided continental Chile in 1950. Its northern border is formed by the Bío-Bío River, which separates it from the Central Chile Zone. The Southern Zone borders the Pacific Ocean to the west, and to the east lies the Andean mountains and Argentina. Its southern border is the Chacao Channel, which forms the boundary with the Austral Zone. While the Chiloé Archipelago belongs geographically to the Austral Zone in terms of culture and history, it lies closer to the Southern Zone.

September 18 is the 261st day of the year in the Gregorian calendar; 104 days remain until the end of the year.