Major cities across Canada may see the return of atheist bus ads next year challenging everything from the existence of God to the tooth fairy.

The Centre for Inquiry Canada, the atheist group behind the "Extraordinary Claims" campaign, said if the Toronto Transit Commission approves their ad, they will be appearing on the city's streetcars and subways early next year. The CFI also hopes to launch the ads in Calgary, Vancouver, Ottawa, Saskatoon and Montreal after the Toronto debut.

The ad featured on the website of the campaign shows a black-and-purple-hued evening sky dotted by stars with a quote inspired by American astronomer, Carl Sagan. The ad reads, "Extraordinary Claims Require Extraordinary Evidence" followed with "Allah, Bigfoot, UFOs, Homeopathy, Zeus, Psychics, Christ," written underneath.

"Science makes extraordinary claims, but it has something to back it up," CFI national executive director, Justin Trottier, told CTV.ca.

Trottier said they are not just challenging the existence of Allah and Christ, but also alternative medicine, psychics, clairvoyance and even childhood icons such as the tooth fairy or the Easter bunny.

The group says it is trying to challenge ideas and ask tough questions to promote reason, science, secularism and freedom of inquiry.

"Why is belief in Bigfoot dismissed as delusional while belief in Allah and Christ is respected and revered? All of these claims are equally extraordinary and demand critical examination," says the campaign's website, www.extraordinary-claims.com.

In January 2009, the Freethought Association of Canada launched a controversial ad that read, "There's probably no God. Now stop worrying and enjoy your life," which raised mixed reactions from the public.

"Bus ads are a great symbol of the public square," Trottier said, adding he hopes to engage the public in conversation with the new ads.

Trottier said the 2009 campaign which he was also a part of, received positive feedback because it reeled in discussions from religious groups as well.

"There was lots of good will from religious communities. This was expressed on the radio and television debates that I had with various Muslim Imams, Rabbis, and even The United Church of Canada," said Trottier.

Meanwhile, the group is currently raising funds for the ad campaign, which will require approximately $10,000 to $15,000 per city. They are halfway to reaching their Toronto goal. The 2009 campaign, which only hit three cities, raised $50,000.