Princess Isabel signs the Golden Law (Lei Áurea), abolishing slavery in Brazil, the last country in the Americas to do so.
A military coup deposes Emperor Pedro II, ending the Empire of Brazil and establishing a republic.
Chile defeats Peru and Bolivia in a war over the mineral-rich Atacama Desert; Bolivia loses its access to the sea.
The United States defeats Spain, gaining Puerto Rico, Guam and the Philippines, while Cuba is freed from Spanish rule.
Francisco Madero calls for revolt against Porfirio Díaz, launching a decade-long revolution involving figures such as Pancho Villa and Emiliano Zapata.
Paraguay fights the Triple Alliance of Brazil, Argentina and Uruguay in a war that devastates Paraguay and kills a large share of its population.
Mexican forces defeat a French expeditionary army at Puebla, a victory later commemorated as Cinco de Mayo.