The Rincón de La Vieja National Park is one of the most diverse ecological areas in the country. Around two volcanoes, Rincón (active) and Santa María (inactive), the park also houses an extraordinary display of local flora and fauna, while being part of the Guanacaste Conservation Area, a World Heritage Site. While plant life is impressive on its own, especially considering the huge concentration of purple orchids here, it is the concentration of volcanoes that truly amazes visitors. The Rincón de la Vieja volcano gave rise to the name of the park and contains nine separate but contiguous craters. It is one of the five largest volcanoes in the Guanacaste region and is believed to be over a million years old. Despite being considered active, it has not erupted since the early 1980s. The park sees a lot of volcanic activity, including vents, fumaroles, and boiling clay pots, and has at least 32 rivers that flow down its sides. There are a number of nature trails for guests, with some reserved for very experienced hikers. The most popular is the 2.5-mile La Pailas trail, which takes approximately two to three hours and is ideal for spotting wildlife, flora, waterfalls, and traces of volcanic activity. The most ambitious hikers can spend eight hours hiking to the top of the Santa María crater, from where you can see Lake Nicaragua on a clear day.