Inside Iran's vast, golden "holy shrine," Islamic pilgrims crowd around the sarcophagus of the country's most significant spiritual leader, the Ayatollah Ruhollah Khomeini.
They are kept at bay by a protective metal cage but slip money through a slot that runs along an interior plastic shield.
Some worshippers settle onto nearby carpets and bow their obeisances toward Mecca. Others cling to the cage, crying for the Imam Khomeini or - forehead pressed to the bars - mouth their prayers with closed-eyed concentration.
Children are lifted to the slot to contribute cash to bolster the Islamic Revolution - which under Khomeini's tutelage in 1979 swept away the pro-West regime of the Shah of Iran. But Iran's political landscape has altered since the mullahs, or clerics, swept into power.
Although vilified by the US as a sponsor of terrorism and feared in Washington for its declared intent of exporting the revolution, Iran simmers with internal problems.
The clerics are divided in their efforts to keep the obedience of Iranians, who have mixed views on the revolution's success.
Iran's Revolution Not in Lockstep
The debate is between conservative clerics - hard-liners in the government who view encroaching Western culture as poison - and a camp considered "moderate" led by President Hashemi Rafsanjani, who has tried to roll back their influence.
Mr. Rafsanjani's second term expires next year, and Iran's current spiritual leader, Ayatollah Sayed Ali Khamenei, stated this weekend that the Constitution would not be amended to allow for a third term in office.
Moderating the revolution
Rafsanjani has been able to "broker the deals in the middle," according to one diplomatic source. Many reform-minded Iranians say that "everything depends" on a continuation of his policies, but few think that any other leader can do so.
These divisions are complicating the recent easing of restrictions - such as those placed on women and on the few opposition leaders, who are now able to speak more openly. But a backlash to the easing has recently surfaced and reportedly spawned a group of hard-line vigilantes called Partisans of the Party of God.
"The revolution happened to us, but our generation is not honest with itself," says a young professional woman, noting her peers' public support and private misgivings about the state of the revolution. "There are two cultures adjusting to one another all the time." If the clerics "push too hard, then like a tightly wound coil [angry Iranians] will suddenly explode."
Still, hard-liners are pushing to regain the upper hand after conservative candidates suffered setbacks in parliamentary elections earlier this year.
"Change is inevitable, whether they like it or not," says Ebrahim Yazdi, the head of the Freedom Movement of Iran, the only tolerated opposition group in the country. "It is coming from inside our own society, from inside the revolution," he says.
"This was a classic mass revolution: People are still loyal to its ideals and to the Islamic republic, but they are fed up and tired of the present deeds of the authorities," Mr. Yazdi says. "As in the past, rights and liberties are being violated."
Endemic corruption, a poor economy, and heavy-handed control of dissent - Yazdi's group, for example, is not permitted to speak out inside Iran and its name is banned from mention by national newspapers - have caused a sense of betrayal and disillusionment, he says.
"[The people] wanted an Islamic revolution, but they are faced with a government of clergy," he says.
"Now they are confronted with harsh measures by those who consider themselves the sole representatives of God on the Earth, the sole interpreters of religion, and the sole combatants ... to rule the country."
The result is a crisis that has brought tough reaction from the mullahs. "One can't resolve the differences by repressing them," Yazdi says. "The traditionalists don't understand this - they want to suppress and eliminate any different ideas."
Still, despite prohibitions on any import of Western culture, Iranians regularly ignore the rules. Satellite dishes hidden in gardens and yards illegally bring CNN to many homes; a thriving black market in videotapes means that a woman covering herself with the mandatory black chador in Tehran may be as knowledgeable and up-to-date on US films as any American.
By contrast, in the past five years only two Western films have been shown officially, Iranians say: "Dances with Wolves," which is deemed to be anti-American, and "The Last Emperor."
Iran's senior religious leaders warn that the Western "culture attack" is "unacceptable propaganda from outside" and say that it is one of the primary threats to the revolution.
"We believe this culture attack is a serious problem, but that doesn't mean we can't do anything about it," says Grand Ayatollah Nasser Makkarem Shirazi, one of Iran's seven top religious leaders. "We believe in Islam, and it will protect us against this attack," he says.
For many young and educated Iranians, the religious and political requirements have brought fatigue with hard-line leaders, whose experiment in Islamic rule - begun by the still-adored Ayatollah Khomeini - appears far from conclusive.
"They want you to think simply, about your house, your food and your family, so that you will not think of anything else," says the young professional woman.
"They must hide everything, like the hair under this veil," she said, rearranging her black scarf.
"If I lift it, you can see the color of the hair and how long it is, and how I put it up. This is what they are afraid of."