Chilean expansionism refers to the foreign policy of Chile to expand its territorial control over key strategic locations and economic resources as a means to ensure its national security and assert its power in South America. Chile's significant territorial acquisitions, which occurred mostly throughout the 19th century, paved the way for its emergence as one of the three most powerful and wealthiest states in South America during the 20th century. It also formed Chile's geopolitical and national identity as a tricontinental state and one of the countries with the longest coastlines in the world.