The Tehran Conference was a strategy meeting of Joseph Stalin, Franklin D. Roosevelt, and Winston Churchill from 28 November to 1 December 1943. It was held at the Soviet Union's embassy at Tehran in Iran. It was the first of the World War II conferences of the "Big Three" Allied leaders and closely followed the Cairo Conference, which had taken place on 22–26 November 1943, and preceded the 1945 Yalta and Potsdam conferences. Although the three leaders arrived with differing objectives, the main outcome of the Tehran Conference was the Western Allies' commitment to open a second front against Nazi Germany. The conference also addressed the 'Big Three' Allies' relations with Turkey and Iran, operations in Yugoslavia and against Japan, and the envisaged postwar settlement. A separate contract signed at the conference pledged the Big Three to recognize Iranian independence.

Tehran is the capital and largest city of Iran and also the largest city in Tehran Province. It also serves as the capital of the province, county and the Central District. With a population of around 9 million and 400 thousand in the city and around 16 million and 800 thousand in the larger metropolitan area of Greater Tehran, The Greater Tehran metropolitan area contains towns like the "New Town of Andisheh", "Islam Shahr", "Shahreh Qods", "Shahryar", "Pakdasht", "Firooz Kooh" and "Shamiran". Tehran is the most populous city in Iran and Western Asia, and has the second-largest metropolitan area in the Middle East, after Cairo. It is ranked 24th in the world by metropolitan area population.