This museum commemorates Costa Rica’s national hero, Juan Santamaría, who gave his life defending the country against a small army led by William Walker, a U.S. citizen who invaded Costa Rica in 1856, attempting to set up a slave state. Housed in a sprawling two-story downtown building with a large open central courtyard, the museum features permanent exhibits about Santamaría and Walker’s filibuster exploits, as well as regularly changing temporary expositions, and evening concerts and theater performances.