This national park is located some 19km north-east of Cartago. The name was derived from the indigenous word “ara-tzu”, which means “thunderpoint”. The attraction here is the largest and highest active volcano in the country. This volcano blew three centuries ago and destroyed the city of Cartago. The city was never restored to its original state, but in respect of some efforts made by Diego de la Haya Fernandez, one of Irazú’s craters was named after him. The volcano erupted again just 40 years ago and destroyed the environments of the surrounding areas, with ash covering most of the Central Valley. The agricultural industry was much affected, but after the eruption the soil became even more fertile. Eventually the park was opened to protect the base of the volcano.