Through a vent, gas-rich magma continuously rises from the underground and accumulates near the surface, which is why the pressure in the volcano should actually increase continuously like in a shaken soda bottle, but the Masaya does not explode. Instead, the gas pressure is reduced, as a magma lake is formed underground, on which gas-containing foam accumulates. The gas escapes from this foam and makes the mountain steam. Therefore, eruptions at the Masaya are rare, with only a little lava flowing down to the valley. During a major eruption on April 23, 2001, some cars parked at the edge of the crater were destroyed by falling rocks. In the visitor center at the entrance of the park you can not only learn about volcanoes, but also about the history of the Chorotega Indians who held ceremonies here to appease the fire god “Chacitutique”. The Spanish conquerors called the volcano La Boca del Infierno (Hellmouth). To ward off the devil, they placed a cross on the crater rim in the 16th century, named La Cruz de Bobadilla in honour of Francisco Bobadilla.

The oldest national park in the country offers the visitor a total of 20 km of hiking trails, the crater lake “Laguna de Masaya”, the two extinct craters Masaya and Nindirí as well as the active crater Santiago. A special feature of the park are the green parrots that nest on the walls of the Santiago crater, although it emits toxic gases. They can be observed in the late afternoon when they return to their nests.