Chief mountain system of Mexico, consisting of three ranges, the Sierra Madre Oriental, the Sierra Madre del Sur, and the Sierra Madre Occidental, enclosing the central plateau of the country; the highest peak is Citlaltepetl at 5,700 m/18,700 ft. The Sierra Madre del Sur (of the south) runs along the southwest Pacific coast.
The Union Jack marks Australia's historical links with Britain. The Southern Cross helped guide early European navigators to the continent. Effective date: 15 April 1954.