In 1494, under the auspices of Pope Alexander VI, Spain and Portugal signed the treaty of Tordesillas. In this treaty they carved up the world politely - a half each - based on a point of longitude roughly down the middle of the North Atlantic Ocean.
Most of South America lay west of the line making it Spanish spoils. The viceroyalty of Brazil’s main cities were east of the line and became Portuguese.
The Viceroyalty of New Granada was well west of the line and fervently Spanish. Thanks to the efforts of Simon Bolivar, the Congress of Panama in 1826 established many of Latin America’s modern countries. Colombia was one of these and it included the isthmus of Panama.
Panama itself became nominally independent in 1903 although thanks to the longstanding Monroe Doctrine, it was really nothing more than an American protectorate (a fate it shared with Cuba, made independent one year earlier in 1902).
The idea of a canal through this narrow isthmus had been envisaged for many years. Sailors and their passengers had long feared and cursed the time-consuming, difficult and treacherous run through Cape Horn in order to reach California and the Northern Pacific Ocean.
The French engineer Ferdinand de Lesseps started the massive engineering project in 1881. Lesseps had the CV for the job. He was responsible for the successful Suez Canal which shortened the journey to India by linking the Mediterranean with the Red Sea. That idea first surfaced in 1832 and work started in 1859. It survived many a building mishap to open 10 years later.
But the Panama project in the malarial ridden Central American swamp proved beyond him. The project went bankrupt 8 years after the start in 1889. He was forced to sell out to the US government for $10 million.
The Panama Canal Act of 1912 gave the US complete control over the zone and they finally completed the massive project shortly before the start of World War I on 15 August 1914. Though thousands died in both the French and American projects, one of the side effects of the canal building project were major advances in the treatment of malaria and yellow fever.
The canal allows ships of less than 300 metres long with a draft of 12 metres access through the isthmus.
Southbound from the Caribbean entrance, ships take an 11km trip through a series of locks to Lake Gaton. Then 40kms across the lake to another set of locks down to the Pacific. The so-called Post Panamax 300+ metre ships must still tackle the vagaries of the Horn.
The Panama Canal Zone was administered by the US for most of the twentieth century and was handed back to the republic of Panama in 1999.