'Rivera' was the Allied meeting between Prime Minister Winston Churchill of the UK and President Franklin D. Roosevelt of the USA at Argentia in the Atlantic Conference, held Placentia Bay, Newfoundland (9/12 August 1941).

Roosevelt had travelled from the USA to Argentia aboard the heavy cruiser Augusta, escorted by battleship Arkansas, heavy cruiser Tuscaloosa and destroyer McDougal, while Churchill arrived from the UK aboard the battleship Prince of Wales escorted by the British destroyer Ripley and the Canadian destroyers Assiniboine and Restigouche.

It was at this meeting that the Atlantic Charter was negotiated for publication on 14 August. The Atlantic Charter laid out a world vision for the period after World War II despite the fact the USA had not yet entered the war. The participants hoped in vain that the USSR, involved in the war from June 1941 as a result of the German 'Barbarossa' invasion, would also adhere to the vision.

In brief, the Atlantic Charter’s eight point were that no territorial gains would be sought by the UK and USA; territorial adjustments must conform with the desires of the people involved; peoples should have the right to self-determination; there should be disarmament after the war; trade barriers should be lowered; there should be freedom from want and fear; there should be freedom of the seas; and there should be an association of nations.

At the subsequent inter-Allied meeting in London on 24 September 1941, the governments of Belgium, Czechoslovakia, Greece, Luxembourg, the Netherlands, Norway, Poland, the USSR and Yugoslavia, as well as representatives of Général de Brigade Charles André Joseph Marie de Gaulle’s Free French movement, unanimously signalled their adherence to the common policy principles set out in the Atlantic Charter.

The Axis powers interpreted these diplomatic agreements as a potential alliance against them, and Adolf Hitler saw them as evidence of collusion between the UK and the USA in an international Jewish conspiracy and agreed, in retaliation, to the implementation of a 'final solution' to the Jewish problem before the conclusion of the war.

Within the Japanese empire, the Atlantic Charter rallied support for the government’s militarists, who pushed for a more aggressive approach to the UK and USA.

On the other hand, this agreement proved to be one of the first steps toward the formation of the United Nations Organisation.

It is worth noting that there was some concern at the time about secrecy and the safety of the British party. Although they joined Prince of Wales in the greatest secrecy, US journalists had noted the absence of Roosevelt from Washington and tied it in with the 'coincidental' absence of Churchill from the House of Commons, and the lack of censorship in a country still at peace allowed press speculation. On 6 August the radio of neutral Switzerland reported rumours that the two heads of government were to meet in Canada. All this was reported even before the start of the meeting, despite the risk it raised for the possibility of a U-boat interception and attack as the British battleship was crossing the Atlantic.