...Forty years ago, Asif came to St. Louis. Then, there was one Nation of Islam mosque, traditionally attended by black American Muslims, in the city. Now, the St. Louis area has at least nine Muslim community centers, which include masjids, also called mosques, for worship, classroom space for instruction and meeting space for social gatherings. Those centers are in Manchester, Overland, Glen Carbon, Ill., and Belleville, Ill., among others. Hasic says people tend to attend the mosques closest to where they live.

Hasic, president of the Islamic Community Center, estimates that about 100,000, Muslims live in the area, about half of them Bosnian, like him. They also come from Pakistan, India, Iran, Iraq, Afghanistan, Somalia, Sudan, and from America.

But no one knows the exact number.

"It's very difficult to come up with any kind of an estimate," says Ahmet Karamustafa, a professor of history and religious studies at Washington University.

His conservative guess, based on his knowledge of the community, is that the population is around 50,000 to 60,000 people.

"I don't know that anyone knows," he says.