With Reza Shah Pahlavi seizing power in 1925, the governement became a major player in Tehran's architecture, whose modernization was an integral part of the program the new king intended for his country. The walls built by Nasseredin Shah were destroyed in 1932, leaving room for wide rectilinear boulevards.


Tehran, capital of Pahlavi

With Reza Shah Pahlavi seizing power in 1925, the governement became a major player in Tehran's architecture, whose modernization was an integral part of the program the new king intended for his country. The walls built by Nasseredin Shah were destroyed in 1932, leaving room for wide rectilinear boulevards; only one of the gates remains to this day. Reza Shah used Iranian and foreign architects to build many official buildings during the 1930s. Nikolai Markov, who built the Alborz High School, André Godard, who built the National Museum of Iran, Maxime Siroux for some faculties Tehran University, Mohsen Forughi for Bank-e Melli and the Faculty of Law of Tehran University, Vartan Avanessian for the Reza Shah apartment complex and the Vartan Orphans School. Many new state buildings were created: the post office, the telegraph office, the police station, the Ministry of Foreign Affairs, the Tehran railway station and so on.
After the expansion and modernization of the city, its surface area is 46 km2, which is eleven times the size it had during the period of Fath Ali Shah. The new streets of the city allow automobile traffic and transform the urban fabric.

In 1943, the city hosted the Tehran Conference, which brought together US President Franklin D. Roosevelt, Soviet Head of State Joseph Stalin and British Prime Minister Winston Churchill. This conference foreshadows the decisions that will be taken at the end of the Yalta Conference. It guarantees the independence and territorial integrity of Iran.

The city grew strongly after the Second World War, especially from the 1960s. In 1966, the royal family moved from the royal quarters of central Tehran to settle in Niavaran; the growing city became more stifling and the sovereigns settled permanently in the northern districts (the residences of the North were previously temporary residences for the summer). Rey and Shemiran, which became suburbs of Tehran, were grouped together administratively in the same year.

Tehran's first urban development plan was defined in 1969. It favors a development of the city on an east-west axis, which contrasts with the North-South trend observed for several centuries. The urban development plan foresees the creation of new residential districts (Shahrak), new industrial districts to the west of the city towards Karaj, the movement of the commercial and administrative center outside the old city limits, and the creation of a rather dense network of intra-urban motorways, modeled on Los Angeles.

In the 1970s, Iran's economy was boosted by the oil boom and new buildings were being built at a rapid pace: construction of new districts such as Ekbatan, subways, highways, etc. Mohammad Reza Shah wants to make Tehran a city with an international vocation and envisages constructions to the height of its ambitions. Starting in 1975, the Pahlavi began building an ultra-modern city of 554 hectares in Tehran, called Shahestan Pahlavi ("Pahlavi Royal City"). This city, destined to become the center and symbol of the power of the Pahlavis, will not see the light of day: the project stops at the stage of purchasing and servicing the land due to budgetary problems and the Iranian revolution.

In 1977, the government had to abandon the 1969 urban plan: the town limits defined by the planning were reached and the real estate pressure was increasing.

In 1978, the Iranian revolution began in Tehran, following a demonstration suppressed by the army in September. It is during this revolution that the Iranian hostage crisis, which begins on 4 November 1979 and lasts 444 days, takes place. More than fifty hostages remained locked in the American embassy until 20 January 1982. The embassy buildings have since been occupied by Iranians, who have dubbed it the "spy nest". The "students of the Imam line" (the group organizing the hostage-taking) has since published a book containing the documents of the CIA and the State Department recovered in the embassy under the title Documents the US Espionage Den. Some of its documents are still classified as "secret" or "confidential".