Ayatollah Khamenei ruled Iran for 36 years after succeeding Khomeini as Supreme Leader

Ayatollah Khomeini returned to Iran on Feb. 1, 1979, after 14 years in exile

Greeted by millions of Iranians flooding the streets of Tehran, Khomeini's return was a defining moment of the revolution. Within days, he appointed a rival prime minister, effectively dismantling the last remnants of the Shah's government and consolidating clerical rule over the new Islamic Republic.

Mohammad Reza Shah Pahlavi ruled Iran for nearly four decades before being ousted by the revolution

The last Shah of Iran came to power in 1941 and pursued rapid Westernization through his controversial reforms. His authoritarian rule, backed by the US, and his feared secret police, SAVAK, fueled mass resentment that ultimately drove him from power in 1979.

Ayatollah Khomeini led the ideological opposition to the Shah from exile

Exiled in 1964 for opposing a law that granted diplomatic immunity to US military personnel in Iran, Khomeini built a large following by smuggling recorded sermons into Iran on cassette tapes. He aimed to replace the monarchy with an Islamic republic governed by religious law.

'Velayat-e faqih' is the religious doctrine that has governed Iran since the 1979 revolution

Meaning "guardianship of the Islamic jurist," the doctrine transfers all political and religious authority to the Shia clergy, with the supreme leader holding ultimate power over the state. Developed by Khomeini in the 1970s, it has served as the foundation of Iran's government since the revolution.

Iranians voted overwhelmingly to establish an Islamic Republic in March 1979

Just weeks after Khomeini's return, Iran held a national referendum to replace the monarchy with an Islamic Republic, and over 98% voted in favor (though the vote was criticized). The vote formalized the revolution's outcome, laying the foundation for a theocratic government that remains in place today.

Iraq invaded Iran in 1980, drawing the new Islamic Republic into a devastating eight-year war

Just a year after the revolution, Saddam Hussein invaded Iran, hoping to exploit its post-revolutionary instability. The brutal conflict killed hundreds of thousands in one of the century's deadliest conflicts and forced Khomeini's government to consolidate power.

Iran's Revolutionary Guard Corps became one of the most powerful forces in the Middle East

Created after the 1979 revolution to protect the new Islamic Republic, the IRGC grew into a force that controls Iran's ballistic missile arsenal, funds, and arms regional proxy groups such as Hezbollah and Hamas, and answers directly to the supreme leader.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

Watch contemporary footage covering the US-backed Shah of Iran fleeing the country in the face of the 1979 Iranian Revolution

The UN found that the Islamic Republic of Iran used genocidal tactics after the revolution

A 2024 report classified Iran's mass executions of political prisoners in the 1980s as genocide and crimes against humanity, finding that thousands were arbitrarily killed under Khomeini's orders by "death committees" targeting perceived religious and political enemies.

Mosaddegh nationalized Iran's oil industry in 1951, threatening Western control of the country's resources

Before nationalization, British companies controlled most of Iran's oil wealth, with little revenue returned to Iranians. Mosaddegh's decision made him a national hero at home but triggered a Western-led embargo and ultimately contributed to the coup that removed him from power.

The primary language in Iran is Persian, also called Farsi

Spoken by the majority of Iran's 90 million people, Persian is one of the world's oldest continuously spoken languages, with a literary tradition stretching back over a thousand years. It is also widely spoken in Afghanistan and Tajikistan.

The ancient succession drama that led to the Sunni-Shia divide

The split that divided Islam into its major branches comes down to succession: after Muhammad's death, Sunnis backed an elected leader, Abu Bakr, while Shia Muslims sided with a member of Muhammad's bloodline, his cousin and son-in-law Ali. That 7th-century disagreement shapes geopolitics today, Ramadan's traditions, and communities worldwide.

The presidential line of succession ensures continuity of government

If the president dies, resigns, or is removed from office, the vice president assumes the presidency. The line then proceeds to the speaker of the House, Senate president pro tempore, and Cabinet secretaries, beginning with the Department of State, established under the Presidential Succession Act.

A backgrounder on North Korea’s power structure

North Korea has been ruled by three generations of the Kim family since 1948, one of the world’s longest-running dynastic dictatorships, where absolute authority flows from the Supreme Leader. Read the Council on Foreign Relations' backgrounder to understand the country’s structure of power.

Supreme Court justices serve for life

The Constitution grants Supreme Court justices lifetime appointments to shield them from electoral politics and outside pressure, a design meant to preserve judicial independence but now widely debated due to longer lifespans and partisan balances of the court.

To reach the afterlife, Egyptians lived in accordance with ma'at, or harmony

The ancient Egyptians held many beliefs about eternal life, fueling entire industries tasked with building tombs for the dead. Their leader, the pharaoh, was believed to be divine, and the lives of ordinary people were punctuated with ritual and myth. Learn more about their religion here.

The mysterious details of Stalin's death

The 73-year-old dictator of the Soviet Union died March 5, 1953, officially from a stroke, on top of nearly a decade of significant medical issues. But evidence suggests the longtime leader might have been poisoned less than a week before at an intimate gathering of Stalin's closest confidantes and advisors. Explore the current evidence for Stalin's alleged murder here.

A short biography of Apple cofounder Steve Jobs

Steve Jobs led Apple for almost a quarter century, first from 1976 through 1985 and then from 1997 through just before his death in 2011. A brief synopsis of his career underscores the impact he made during that timespan, across everything from technology to smartphones, moviemaking, retail and much more.

See all 16 Fed Chairs ranked by stock market performance

Sixteen people have held the office of Fed Chair since 1913, with varying results. From the Fed’s first leader, Charles Hamlin, to Jerome Powell, see in a ranked list how stocks fared for each chair within distinct macroeconomic conditions.

Ayrton Senna and Alain Prost had one of the sport's most intense rivalries

The men were teammates at McLaren in the 1980s, but you wouldn’t know it watching them on the track. Senna dominated the sport from 1984 to 1994, but Prost, who retired in 1993, is considered the best in F1 history.

Budget airline Spirit announced its shutdown on May 2, 2026

After filing for bankruptcy twice, there were a multitude of reasons for the airline's shutdown, including an increase in jet fuel prices due to the conflict in Iran in the first half of 2026.

Chernobyl's remaining reactors kept running for 14 years after the explosion

Due to energy shortages in Ukraine, Chernobyl's other undamaged reactors continued operating for years. Units 1 and 2 operated until 1996 and 1991, respectively, while Reactor 3 remained online until December 15, 2000, when Ukraine finally shut down the plant.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

'The man who views the world at 50 the same as he did at 20 has wasted 30 years of his life.'

- Boxing champion Muhammad Ali (1942-2016)

Who was Maximilien Robespierre, leader of the Reign of Terror?

This 28-minute podcast details the life and death of French revolutionary Maximilien Robespierre, who was killed by the people he previously led in 1794. Robespierre is considered the leader of the Revolution's Reign of Terror, a period of intense...

Explore the fraught relations between the United States and Cuba since 1959

From the Cuban Missile Crisis and decades of economic embargo to President Obama's normalization efforts and President Trump's reversion to "maximum pressure," US-Cuba relations have fluctuated between hostility and fleeting diplomacy since Fidel Castro's 1959 revolution.

Quantum superposition makes Schrödinger’s cat both dead and alive until observed

Erwin Schrödinger's famous cat thought experiment illustrates how quantum objects can exist simultaneously in multiple states. This superposition allows electrons to behave as particles and waves, enabling chemical bonds and the function of modern electronics.

The power and influence of the American presidency have expanded significantly over time—far beyond what the founders envisioned.

The identity of the Tank Man in the iconic photo from the 1989 Tiananmen Square protests remains unknown and was possibly killed.

See a ranking of the best (and worst) Federal Reserve Chairs since 1914 out of the 16 men and women who have held the office since.

In 2026, Finland was named the world's happiest country for the ninth consecutive year based on its wealth, social safety network, and high life expectancy, among other factors.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Jimmy Carter signed a 1978 bill that legalized home brewing, a move credited with kick-starting the craft beer industry.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-2016.

Urushiol, the oily toxin in poison ivy, can remain allergenic on clothing for years.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.