This lake lies in a great pit or caldera created by the wrecking in prehistoric times of the volcano Mount Mazama, which according to geologists once had an altitude of about 14,000 ft.
Above the surrounding tableland; the upper portion of the mountain fell inward, possibly owing to the withdrawal of interior lava, and left a crater-like rim, or caldera, rising 2000 ft.
During the night of the 23rd of April, and whilst the " Blanco Encalada " was lying quietly at anchor, a torpedo boat called the " Almirante Lynch," belonging to the Balmaceda faction, steamed into the bay of Caldera and discharged a torpedo at the rebel ship. The " Blanco Encalada " sank in a few minutes and 300 of her crew perished.
South-east by rail from Caldera, the principal port of this great mining district.
Communications.-Railway construction in Chile dates from 1850, when work was begun on a short line between Copiapo and the port of Caldera, in the Atacama desert region.
The Caldera & Copiapo railway (built 1848-1851 and one of the first in South America) extends beyond Copiapo to the Chanarcillo mines (50 m.) and other mining districts.
Its port, Caldera, 50 m.
Among the most frequented of these are Valparaiso, Coquimbo, Caldera, Iquique and Arica.