WEST ST. LOUIS COUNTY — The billboard sits low in the sky — below another one for a real estate broker — as if it's uncertain it wants to trumpet its message too loudly.

"Imagine no religion," it reads in a medieval-looking font, framed in a colorful stained-glass window pattern.

The small billboard, on a strip of Manchester Road crowded with retail outlets, also gives the Web address for its sponsor, the Wisconsin-based Freedom From Religion Foundation.

On its website, the foundation says it "works as an umbrella for those who are free from religion" and, with 14,000 members, calls itself the country's largest association of atheists and agnostics.

This is the group's first billboard in Missouri, but it has bought billboard space in 18 states since launching what it calls its "educational campaign" in 2007. Its other billboard messages — all in the same church-y design — include "Beware of Dogma" and "Reason's Greetings."

"We want to promote our viewpoint and make it socially acceptable to be an atheist," said the foundation's founder and co-president, Annie Laurie Gaylor.

But a billboard using John Lennon's words to champion a message of unbelief sounds more like evangelism than civil rights.

"We are proud of our views and want to proclaim them," Gaylor said. "We want to take our message to the un-Massed masses."

The world's two largest religions, Christianity and Islam, claim more than half the world's population because tenets of both faiths instruct followers to recruit more members. But Christians and Muslims (and practitioners of other religions) teach a belief in creeds, doctrines and rituals that offer explanations for the universe and govern their members' moral lives.

Can atheist groups evangelize to religious believers by advocating an alternative belief in nothing? What replaces the creeds and doctrines and rituals that give meaning and purpose to billions around the world?

The foundation's answer is that nothing replaces belief, and that's exactly what will save the world.

"We feel society would be better without religion," Gaylor said. "Religion has caused more problems than it's solved. It's holding back progress and holding back individual minds. In general, religion is a very harmful idea."

Gaylor said even the most benign aspects of organized religion — the lessons and figures that most of the world hold up as examples of pure good — were damaged by their association with faith. Mahatma Gandhi, for instance, defined the "Hindu creed" as the "search after truth through nonviolent means."

"The caste system is a terrible scourge on India," Gaylor said. "That's part of the legacy of Hinduism."

What about the message behind the Beatitiudes that Christ delivered in the Sermon on the Mount? The meek shall inherit the earth, blessed are the peacemakers, etc.

"I have a lot of objections to the Beatitudes which encourage meekness, docility and not changing this world," Gaylor said. "That's a good message for rulers to give to those who they rule over."

Despite the use of church marketing methods familiar on the American landscape, Gaylor denies that her organization is using evangelical Christian tactics.

"We're not knocking on peoples' doors telling them not to go to church, and we're not on corners yelling at people to give up their religion," Gaylor said. "We're not acting as religion does."

The 2008 American Religious Identification Survey found the number of people who claim no religion has nearly doubled since 1990 to 15 percent of the population, a finding the Freedom From Religion Foundation called "heartening."

With only 200 members, Missouri's membership in the foundation is one of the country's smallest. Some of those local members helped pay for about half the $750 billboard rental fee.

One of those members picked its location on Manchester Road, just west of Weidman Road, so that it would be close to his home. Gaylor wouldn't name the member and said the member could not be interviewed because he didn't want his employer to know he is an atheist.

Christ, Prince of Peace Catholic Church sits on Weidman, about a third of a mile from the billboard. The St. Louis area's largest mosque, the Islamic Foundation of Greater St. Louis, is also on Weidman, just up from the church, about a half-mile from the billboard.

Gaylor said the presence of those worship sites "was not one of our motivations" in placing their ad on a nearby billboard, but, she said, "that sounds like a perfect place for it."

The Rev. Robert Corbett, associate pastor of Christ, Prince of Peace, said he respects the foundation members' right to express themselves.

"We're certainly not going to tear the thing down," Corbett said. "But being against something is no way of promoting something else."

He said religion propels believers to do good in the world.

"Religion is going to prompt people to do things beyond themselves," he said. "The first thing about religion is that you're accountable to the God who created you. We're accountable for what we do, or fail to do."

Mufti Minhajuddin Ahmed, imam of the Islamic Foundation, also cited the rights of the organization's members to express their views. But he took the premise of the billboard seriously.

"If I were to imagine a world without religion, it would be a very dark world," Ahmed said. "Compassion, kindness, love for creation — those things come from religion. Imagining a world without religion is a scary thought to me."

Another mile up Wiedman Road, the Hindu Temple of St. Louis shares land with the Mahatma Gandhi Center. In front of the center, under a bust of Gandhi, some of the Indian leader's words are etched in marble, preserved for the future so generations to come will ponder them.

"I have nothing new to teach the world," it says. "Truth and nonviolence are as old as the hills."

The Freedom From Religion Foundation has rented the Manchester Road billboard for just one month. On Oct. 1, a different, disposable message — one for fast food, or a radio station or a soft drink — will replace the foundation's invitation to "Imagine no religion."