That first Persian Empire was conquered by Alexander the Great from Greece. Later, a second Persian Empire was conquered by Arabs. Then came invasions by Turks and Mongols. Finally, with the establishment of a Third Persian Empire in the 16th century, this culture enjoyed a renaissance. While it's weathered wave after wave of conquerors, the essence of today's Iranian culture is still rooted in that first Persian Empire from 2,500 years ago.

Newsreel: Persia; At the turn of the century, a poor agricultural country, rich only in legend and undeveloped natural resources…

In the 20th century, with the discovery of its vast oil reserves, Iran became entwined with the West.

Newsreel: …oil was struck at last and drilling commenced…

During WWII, Iran was a vital oil resource for the Allies. After the war Iran's young shah, or king, Mohammed Reza Shah Palavi became more closely involved with the West. Oil flowed easy and he was a friend of western oil companies. Then things changed…

Oil again poses a threat to peace and the Middle East again becomes a trouble spot as Iran's vast petroleum reserves aroused nationalists…

In 1951 the popular Prime Minister Mossadegh nationalized Iran's foreign-owned oil industry. With the resulting turmoil, the shah was forced into exile. This is when the troubled relationship between Iran and the United States began.

Every Iranian school kid knows the date: 1953. That's when the CIA engineered a coup that over threw the democratically elected prime minister Mossadegh. He had angered the West by nationalizing Iranian oil. So they installed the pro-Western shah instead.

Newsreel: Former premier Mossadegh's ruined house is a mute testimony to three days of bloody rioting culminating in a military coup from which the one time dictator of Iran fled for his life. The Shah who had fled to Rome comes home backed by General Zahedi military strong-man who engineered his return to power. Iranian oil may again flow westward.

Back on the throne, the shah allowed Western oil companies to run Iran's oil industry again. With the profits, he modernized the country. Through the 60s there was a return to stability and the shah was a key American ally in the Middle East.

The shah ruled in royal opulence from grand palaces. He enjoyed summers in this one until the late 1970's. Strolling through its fine rooms visitors are reminded how the shah lived in extreme luxury. But his materialistic decadence and pro-Western policies offended Iran's conservatives and alienated religious and political groups. Angry people hit the streets.

The unrest led to crackdowns by the shah's forces that tortured and killed thousands. All of this emboldened a revolutionary movement and burned into the national psyche a fear of American meddling in internal Iranian affairs.

After 25 years of the Shah's rule, the Islamic Revolution threw him out and brought Ayatollah Khomeini back from exile. That Revolution and the Ayatollah established the Islamic Republic which rules to this day.

Walking the streets here, I felt a disturbing presence of government. This is not a democracy. In 1979 the new government brought Iran not freedom, but what they call a "Revolution of Values" – it legislated morality such as no alcohol, and no casual sex. As far as many parents are concerned here, it's family values.

Iran is ruled by a theocracy. They may have a president, but the top religious official, a man called "the supreme leader" has the ultimate authority. His picture — not the president's — is everywhere.

Religious offering boxes are on every street corner. The days when the shah's men boasted that mini-skirts in Tehran were shorter than those in Paris are clearly long gone. Women must dress modestly and are segregated in places like classrooms and buses.

And yet here in the Islamic Republic of Iran, to me, the atmosphere felt surprisingly secular compared to other Muslim countries.

Skylines are not punctuated with minarets; I barely heard a call to prayer. Except for women's dress codes and the lack of American products and advertising, life on the streets here seemed much the same as in secular cities elsewhere in the developing world.

While relatively uncluttered with commercial advertising, there are plenty of billboards and murals and they pack a powerful propaganda message…. Some religious murals are uplifting — this one is a Shiite scripture claiming; the most caring help is to give good advice.

Yet others are troubling and hateful — this one condemns what's considered American Imperialism with skulls and dropping bombs rather than stars and stripes. And this one glorifies Hezbollah fighters and their struggle with Israel which many here consider Americas' 51st state. This mural honors a martyr — one of hundreds of thousands who died fighting Saddam Hussein back in the 1980s.

These murals mix religion, patriotism, and a heritage of dealing with foreign intervention. While I find some of them offensive, I see in these murals the fear and the spine of a people whose values are threatened.

The greatest concentration of anti-American murals surrounds the former US Embassy. In 1979, Iranian university students successfully stormed the embassy, they took 52 hostages, and held them with the world looking on for 444 days.

Some Iranians claim the hostage crisis was a way to radicalize the Islamic revolution and put the hard-liners in power. Others say it was a pre-emptive strike to stop the USA from orchestrating a military coup designed to overthrow their theocracy and put the shah back in power. They also wanted to force the extradition of the shah who was in exile in the United States.

Today it feels like the hostage crisis is old news and younger Iranians have moved on. The murals seemed to drone on like an unwanted call to battle — a call which people I encountered it seems had simply stopped hearing.