El Malpais National Monument is a National Monument located in western New Mexico, in the Southwestern United States. The name El Malpais is from the Spanish term Malpaís, meaning badlands, due to the extremely barren and dramatic volcanic field that covers much of the park's area. It is on the Trails of the Ancients Byway, one of the designated New Mexico Scenic Byways. Geography and geology The lava flows, cinder cones, and other volcanic features of El Malpais are part of the Zuni-Bandera volcanic field, the second largest volcanic field in the Basin and Range Province. This volcanically active area on the southeast margin of the Colorado Plateau is located on the ancient Jemez Lineament, which provides the crustal weakness that recent magmatic intrusions and Cenozoic volcanism are attributed to. The rugged pahoēhoē and ʻaʻā lava flows of the Zuni-Bandera eruptions (also called the Grants Lava Flows) filled a large basin, created by normal faulting associated with the Rio Grande Rift, between the high mesas of the Acoma Pueblo to the east, Mt. Taylor to the north, and the Zuni Mountain anticline to the northwest. Vents associated with these flows include Bandera Crater, El Calderon, and several other cinder cones; more than a dozen older cinder cones follow a roughly north-south distribution along the Chain of Craters west of the monument. Features El Malpais has many lava tubes open to explore (unguided) with a free caving permit, available at NPS-staffed facilities. There are currently four caves accessible by permit: Junction and Xenolith caves in the El Caldron area, and Big Skylight and Giant Ice caves in the Big Tubes area. From December 2010 to June 2013, all caves were temporarily closed to recreational use to protect bats from the spread of White Nose Syndrome (WNS) until a permitting process, including visitor screening for WNS, could be implemented. A nearby scenic overlook at Sandstone Bluffs offers spectacular panoramic views over the monument's lava flows. Natural history Some of the oldest Rocky Mountain Douglas-firs (Pseudotsuga menziesii subsp. glauca) on Earth can be found living in El Malpais Monument. In 2020, a new population of hart's-tongue ferns (Asplenium scolopendrium) was discovered inside of a cave with basaltic lava flows in El Malpais, which represents the first confirmed population of the species in the United States or Canada west of the Mississippi; all other known populations of the fern are around the Great Lakes,