A few blocks north of the park is this excellent little museum that charts the causes and course of the Salvadoran civil war. Highlights include the collection of antiwar posters from throughout the world, the stark color photos of life inside guerrilla camps, the incredible assortment of Soviet and US weapons, and the stories of those who died in action; there is also a crater left by a 500lb bomb. It makes for a somber, stirring visit.
The museum is also the contact point for ex-guerrilla guides who can help put the exhibits in context and provide detailed explanations. Their stories are compelling, though not many guides speak English. They can also take visitors on fascinating guided trips throughout the war zone. The most popular destination is El Mozote.