On February 1, 1979, Ayatollah Khomeini returned to Tehran from exile in France. When a reporter asked him how he felt upon his return to Iran, Khomeini replied: "Nothing — I feel nothing." Some analysts interpreted his remarks as the Shiite leader's idea about embarking on a "divine mission" where emotions hardly mattered.

Two months before Khomeini's return to Iran, an estimated six to nine million people took to the streets in the country's major cities. The demonstrations were largely peaceful, compared to the violent September 8, 1978, protests. The Shah regime, headed by Shah Mohammed Reza Pahlavi, had realized that its time in power was over and that they could not stop Khomeini's return.

The revolutionary mood was so intense in Tehran that even many women celebrated Khomeini's return, ignoring the fact that Khomeini had slammed Shah's measures for women's emancipation in exile. In 1963, the Shah of Iran granted women the right to vote.

In 1971, the Shah and his wife Farah Diba (seen in the picture) staged a lavish spectacle on the ancient site of Persepolis to mark the "2,500th anniversary of the Iranian monarchy." Many heads of state attended the event. Khomeini, in his message from exile, condemned the monarchy as "cruel, evil and un-Islamic."

Under pressure from the Islamic Revolution, the Shah (left) had left Iran on January 16, 1979. After spending time in several countries, he succumbed to cancer on July 27, 1980 in Cairo, Egypt.

In the beginning, women's rights were not a major issue for the Islamic revolutionaries. They only imposed hardline Islam after consolidating their victory.

Upon Khomeini's return to Iran in 1979, the military did not confront the protesters. On February 11, the army declared itself neutral. Despite that, the revolutionaries executed several generals in February and April.

Soon after his return, Khomeini declared the monarchy, the previous government and parliament illegal, and said he would appoint a government "because of the fact that this nation believes in me." According to Iran experts, it was not self-deception but reality.

Mehdi Bazargan, a scholar and pro-democracy activist, had campaigned against the Pahlavi dynasty, for which he had been incarcerated for several years. Khomeini appointed him as his first prime minister, although Bazargan was critical of him as well. Bazargan had called Khomeini a "turbaned Shah" after a meeting with the Ayatollah in Paris. He remained in office for only nine months.

In November 1979, radical Iranian students seized the US Embassy in Tehran and took the embassy staff hostage. The students were fearful of Shah's return to power with US help. Khomeini took advantage of the situation. He dismissed his opponents as "US allies."

In 1989, Ayatollah Ali Khamenei was elected by the expert council to succeed Khomeini. Khamenei, to this date, has the ultimate power over all state institutions. Although the 79-year-old does not have the same charisma as his predecessor, he represents the policies of Iranian hardliners who refuse to reform the system and continue to persecute dissidents.

Hezbollah, or Party of God, was conceived by Muslim clerics in the 1980s in response to the Israeli invasion of South Lebanon in 1982. The Shiite group has a political and military wing.

Hezbollah emerged in the 1980s as an amalgamation of Shiite militias and played a major role in the Lebanese civil war. It used guerrilla warfare to drive Israeli forces out of South Lebanon — Israel withdrew in 2000. Israel and Hezbollah fought another war in 2006. Its defense of Lebanon against Israel had won it cross-sectarian support and acceptance in Lebanese society.

Since its creation, Hezbollah has received military, financial and political support from Iran and Syria. Today, Hezbollah's military wing is more powerful than Lebanon's own army and has become a major regional paramilitary force.

Hezbollah turned its focus to politics following the end of Lebanon's 1975-1990 civil war. It represents a large section of the Lebanese Shiite population and is allied with other sectarian groups, including Christians. Their political development has mostly come under Hassan Nasrallah (pictured), who became the group's leader in 1992.

Unlike other parties in Lebanon's multi-sided 1975-1990 civil war, Hezbollah did not disband its armed wing. Some Lebanese political groups, such as Prime Minister Saad Hariri's Future Movement, want Hezbollah to put down its arms. Hezbollah argues its militant wing is necessary to defend against Israel and other external threats.

A number of countries and bodies, including the United States, Israel, Canada and the Arab League, consider Hezbollah a terrorist organization. However, Australia and most of the European Union differentiate between its legitimate political activities and its militant wing.

Hezbollah has been one of the main backers of Syrian President Bashar Assad in the country's civil war. Its entrance into the war helped save Assad, one of its chief patrons; secured weapons supply routes from Syria and formed a buffer zone around Lebanon against Sunni militant groups it feared would take over Syria. As a result it has won considerable support from Shiite communities in Lebanon.

Lebanon has long been at the center of regional power struggles, particularly between Saudi Arabia and Iran. However, Hezbollah's military and political ascendancy, as well as its intervention in Syria, have also helped stoke Sunni-Shiite sectarian tensions in Lebanon and across the region.

Iran and Hezbollah have increased their political and military strength through the war in Syria. Israel views this as a threat and has carried out dozens of airstrikes on Iran/Hezbollah targets in Syria. Israel has vowed to not let Iran and Hezbollah create a permanent presence in Syria. There is growing concern of another war between Hezbollah and Israel that could draw in Iran.