The Antarctic Treaty applies to the entire region south of 60° South Latitude. It effectively stops nations from making territorial claims or from exploiting Antarctic resources.
The Antarctic Treaty was negotiated by 12 countries in 1959: Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, UK, USA and USSR.
The fundamental aim of the Antarctic Treaty is that Antarctica "shall continue forever to be used exclusively for peaceful purposes and shall not become the scene or object of international discord". It prohibits military activity and allows for freedom of scientific investigation in Antarctica.
Original text of the Antarctic Treaty
Article I — Antarctica shall be used for peaceful purposes only. There shall be prohibited, inter alia, any measure of a military nature, such as the establishment of military bases and fortifications, the carrying out of military manoeuvres, as well as the testing of any type of weapon.
Article II — Freedom of scientific investigation in Antarctica and cooperation toward that end shall continue, subject to the provisions of the present Treaty.