In the morning visit the Sierra Negra Volcano, which is the largest basaltic caldera in the Galapagos with a diameter of 6.2 miles (10 km). The site offers impressive views and the opportunity to observe up to seven species of finches and a rich display of vegetation. The north side of the caldera provides evidence of its most recent volcanic activity in 2005. In the afternoon visit the Arnaldo Tupiza Breeding Centre which is located about one mile (1.5 km) from Puerto Villamil. Here, tortoise populations from South Isabela, Sierra Negra Volcano, Cerro Azul, Cazuela, Cinco Cerros, Roca Union, San Pedro, Tables and Cerro Paloma have been bred in captivity. In total there are 330 juvenile and adult tortoises.