Final answer:
William Walker was an American adventurer and filibuster who gained control of Nicaragua in 1856, aiming to expand the influence of the pro-slavery South. He made slavery legal, reopened the slave trade, and briefly served as the country's president before being chased out and executed.
Step-by-step explanation:
William Walker was an American adventurer and filibuster who gained control of the Central American nation of Nicaragua in 1856. Walker supported slavery and aimed to expand the pro-slavery South's influence in Central America. He made slavery legal in Nicaragua, reopened the slave trade, and was elected president of the country for a brief period. However, he was eventually chased out of Nicaragua, captured by the British, and executed by firing squad in Honduras.