The Gruta das Torres (Portuguese: Grotto of Towers), is a lava cave, a geological formation of volcanic origin formed from the flow and cooling of subterranean magma rivers. This formation is located outside the parish of Criação Velha, in the municipality of Madalena, on the western flanks of the island of Pico. The cave system formed from a series of pāhoehoe lava flows which originating from the Cabeço Bravo parasitic cone about 500 to 1500 years ago. The caves are a group of interconnected lava tubes between 0.5–22 metres (2–72 ft) width, created from both pāhoehoe and ʻaʻā types of lavas generated during different geological periods. It has a height between 1.1 and 15 metres (3.6–49 ft) and is located at an elevation of300 metres (980 ft). With an estimated length of over 5.2 km (3.2 mi) it is the longest lava cave in the Azores. Access to the cave was managed by the Mountaineering Association (“Os Montanheiros” – Núcleo da Ilha do Pico).