Nevado del Ruiz is an active stratovolcano that is located between the Caldas and Tolima departments. Since becoming active, Nevado del Ruiz has had three major eruptions. These eruptions are known for their pyroclastic flows and massive lahars. The last major eruption occurred in 1985, killing 23,000 Colombians and destroying several towns. YouthMappers created and improved existing infrastructure data, with a focus on tracing buildings, roads, bridges, and inland water features for use by the USAID Office of Foreign Disaster Assistance and USGS monitoring efforts.