Masaya is a caldera located in the department of Masaya, 20 km south of Managua, Nicaragua. It is Nicaragua's first and largest National Park, and one of 78 protected areas of Nicaragua. The complex volcano is composed of a nested set of calderas and craters, the largest of which is Las Sierras shield volcano and caldera. Within this caldera lies a sub-vent, which is Masaya Volcano sensu stricto. The vent is a shield type composing of basaltic lavas and tephras and includes a summit crater.