It is still rare to walk into a house of worship and find an audience that even remotely reflects the country's growing diversity.

But there is at least one small exception to this trend - worshipers in the Baha'i faith, a religion founded in Iran in the 19th century that now has nearly 6 million practitioners worldwide.

In the Boston area, 1,500 Baha'is are a veritable United Nations of the faithful - African-Americans, Asian-Americans, Latinos, and immigrants from China, Japan, Cambodia, Iran, Iraq, and several Latin American countries.

Racial and ethnic harmony is one of the tenets of Baha'i, which was founded by Baha'u'llah, an Iranian spiritual leader who sought to establish a religion that could cultivate a more egalitarian world without competing with other faiths.

"We are all members of one family," explained Julie Pau, a native of Malaysia who lives in Brookline and studies at Lesley College in Cambridge. "We all have the same color blood. The idea of world unity is a very appealing aspect of Baha'i."

Perhaps the most intriguing core beliefs of the Baha'i faith involve its teachings about the oneness of all religions. Baha'i holds that God has revealed himself throughout history through divinely inspired messengers, including Abraham, Moses, Jesus, Buddha, Krishna, Mohammed, and Baha'u'llah himself.

The teachings of these messengers varied to meet the needs and challenges of the times. Within this framework, Baha'u'llah claimed that Baha'i is a reflection of God's message for our times. While rituals and traditions may vary, Baha'is believe that they all share common themes of social and economic justice.

"If you read the Koran, the Bhagavad-Gita, the Bible, native American mythology, and so on, they all speak to the same principles," said Robin Chandler, a professor at Northeastern University who was introduced to Baha'i as a teenager in Cambridge. "As Baha'is we are being asked to return to those essential principles so we can achieve the peace God expects of all of us. Baha'i principles are marching orders from God."

Among those principles are the elimination of the gap between poor and rich, the importance of education, and recognition that science and religion can coexist. Baha'is are expected to embrace chastity and monogamy, pray daily, and observe an annual period of fasting. The faith has no clergy but is governed by elected bodies.

Baha'is worldwide run environmental and economic development projects as well as schools and literacy programs. In Boston, the Baha'i community runs a school that teaches English as a second language.

Many practitioners find the Baha'i faith's utopian goal particularly appealing.

"Baha'i made so much sense to me in many different ways, particularly the idea that we are to bring people together," said Soroush Shakib, a computer engineer from Acton who was born in Iran.

Although Shakib's parents were Baha'is, that did not automatically make Shakib a Baha'i. Baha'i requires its followers to choose the faith.

"We are told to investigate for ourselves and make sure that our beliefs are in line with Baha'i," Shakib said.

Dr. Changiz Geula, a professor at Harvard Medical School who also was born in Iran, said, "There was a newness and progressive quality about Baha'i that made me feel I had no other choice but to be a Baha'i."

Baha'i has been one of the fastest-growing religions of the past century. "We're just in the first 150 years of what we feel is a new dispensation from God," said Chandler, the Northeastern professor. "We don't expect the achievement of what sounds like a utopian world to happen any time soon. It will take several hundred years before we even begin to see glimmers of solutions to the world's problems."