The Sierra Negra is a volcano located in Puebla , Mexico , near the state line with Veracruz . At its summit is the Alfonso Serrano Large Millimeter Telescope (LMT), the world's largest radio telescope in its frequency range. ^{[ 1 ]} At 4,580 meters (15,000 ft) above sea level , ^{[ 2 ]} it is the fifth highest peak in the country. However, because it is adjacent to the much higher and more famous Pico de Orizaba or Citlaltépetl ( 18,000 ft ), the Sierra Negra is often overlooked and excluded from Mexican mountaineering guidebooks . ^{[ 3} ]

• https://es.wikipedia.org/wiki/Sierra_Negra