The article mentions it, but I only learned recently that Bolivia did not used to be landlocked. Chile took Bolivia's coastline somewhat recently (late 1800s/early 1900s).
> The dispute began in 1879, when Chile invaded the Antofagasta port city on its northern border with Bolivia as part of a dispute over taxes. Within four years Chileans had redrawn the map of South America by taking almost 50,000 square miles of Bolivian territory, including its 250-mile coastline on the southern Pacific Ocean. Bolivia accepted this loss in 1904, when it signed a peace treaty with Chile in return for a promise of the “fullest and freest” commercial access to port.