A strenuous hike along Sendero 23 to the summit of Tenerife's 2nd highest peak at over 10,000ft. Pico Viejo is a volcano located on the island of Tenerife. It is the second highest peak of Tenerife and the Canary Islands (after the Teide), with a height of 3,135 m above sea level, and a huge crater approximately 720 metres in diameter. The volcano is part of the Teide volcanic complex, which began forming about 200,000 years ago in the center of Tenerife. Its crater is one of the satellite craters around El Teide. It last erupted in 1798, and it is estimated that it ejected around 12 million m³ of lava over three months forming a black colored surface, which is different from the rest of the volcano area, which are known as the Teide noses.