Final answer:
Simón Bolívar first liberated Venezuela from Spanish control. After a prolonged struggle and the decisive battle of Carabobo in 1821, Venezuela achieved independence. Bolívar's success continued as he helped liberate other South American nations, forming Gran Colombia.
Step-by-step explanation:
The first South American country that Simón Bolívar liberated was Venezuela. Bolívar, also known as 'The Liberator', began his revolutionary campaign by leading a revolt in his birth colony of Venezuela. The struggle for independence in Venezuela set the stage, and on July 5, 1811, the colonial rebels declared their independence from Spain. Despite this declaration, it was not until after a series of conflicts that Bolívar won a decisive battle against the Spanish at Carabobo in 1821, securing final victory from Spain for Venezuela.
Simón Bolívar's efforts in the liberation of South American colonies did not stop with Venezuela. He went on to play an essential role in the liberation of several other territories that eventually formed part of Gran Colombia (including present-day Colombia, Ecuador, and Panama) and was instrumental in the independence movements across the continent.