Panama lies at the southern end of Central America. It borders Colombia to the south and Costa Rica to the north. The region was first settled by Spain in the 1500s. Panama broke ties with Spain in 1821 as a part of the Republic of Gran Colombia. It remained unified with Colombia until 1903 when, with the aid of the United States, Panama separated from Colombia to facilitate the construction of the Panama Canal. Today, with approximately 15,000 ships passing through it each year, the canal accounts for a large portion of the country’s GDP and is a mainstay of international commerce.