Scene depicted at dusk, pink sky with dark and white clouds. On the left, large trees with a stream running over rocks. Ahead, man on horseback (Osório, points towards the camp (on the right) and looks at the companions behind). Osório has a white beard and black mustaches, he wears a hat with a brim, caramel poncho and under his black jacket and white pants; beside him, a man on horseback carrying a spear and wearing a white cap and striped poncho. Next, several soldiers on horseback moving through several white triangular-shaped huts; we see white smoke coming from some fires. At the top of a tree; small hut (guardhouse) and next to it, a ladder. Inside, an armed soldier. Soldiers move around the camp and cannon cannons can be seen in the repair of woodThe Chaco Pass was an episode of the Paraguayan War, dealing with a maneuver by the Brazilian Imperial Army, which began on June 22, 1867 under the command of General Osório, whose aim was to surprise the Paraguayan army. In this depiction of battle, Pedro Américo shows the border between Brazil and Paraguay. Nature dominates the composition: on one side, we see a forest, a symbol for the Brazilian territory. The flooded lands of the Chaco region, representing Paraguay, stand on the other. Américo focuses on the moment the Brazilian army spots the Paraguayan camp. The battle is about to begin.