The Desventuradas Islands ('Unfortunate Islands') are relatively small oceanic islands, located approximately 850 km off the coast of Chile. Both islands are of volcanic origin, and the flora and fauna are of great scientific interest, though there is little known about it. San Ambrosio rises from the sea as sheer cliffs on almost all sides, is 4 km long by 850 m wide, and primarily basaltic. San Felix is slightly smaller and has two small peaks, reaching 193m, which are denuded by high winds. The vegetation is a miniature mosaic of matorral, barren rock, various size trees, and shrubs mixed with ferns and perennial herbs.
There are no permanent sources of fresh water on the islands. Vertebrates inhabiting both islands are exclusively limited to birds. Ten species of marine birds and one land bird species, some of them endangered, make their nests on or visit the islands.
Because of their isolation and difficulty of access, there are no human settlements on these islands, but on San Félix island there is the permanent presence of a detachment of the Chilean Navy.