In a small corner of Hopkins, there's a sign of the end of the world.

"Save the date!" the 11th Avenue billboard reads. "Return of Christ/May 21st, 2011." On that day, according to the group behind the billboard, believers will be raptured up to heaven and the whole world will witness an earthquake that will raise bodies from graves. Those left behind will face exactly 153 days of trial and tribulation before the world ends Oct. 21.

The billboard is one of 25 that Raleigh, NC-based WeCanKnow.com installed throughout the Twin Cities as part of a marketing campaign in about a dozen states. The group is a family-run affair of only about three or four people. Allison Warden (no relation to the author of this article) is the de facto spokeswoman. Her mother came up with the idea for the website and approves the literature that goes on it. Warden's best friend from high school is the webmaster. The group doesn't disclose the amount it spends on billboards, bus benches and other advertising, but Warden said the campaign was funded by pooling private donations made explicitly for that purpose.

Warden, who briefly lived in central Minnesota a decade ago, is certainly no hair-shirt-wearing prophet. She's a payroll clerk by day who spends her free time trying to persuade people that the end times are near. "We're just regular people that have had the most average American life that people can have," she said—adding that May 21 is God's date, not hers. "I'm 29 years old. If I were to set a date, don't you think I would have pushed it back farther?"

WeCanKnow is not affiliated with any church, denomination or group—in fact, it believes that churches are flawed and that a biblically prescribed "church age" has ended. But it draws heavily on ideas from Oakland, CA-based Family Radio Worldwide—a network of 66 stations steered by 89-year-old Harold Camping. To maximize the reach of these ideas, WeCanKnow selected advertising sites, such as the Twin Cities, where Family Radio doesn't already have stations.

Camping made news back in the '90s when he predicted that the world would end in September 1994—albeit acknowledging the possibility that he could be wrong. He and his followers say now that he stumbled over a few scriptures and that the new dates are ironclad.

Said Warden: "This isn't a person's opinion. It's there in black and white." Christianity has a deep history of belief that end times are imminent. The early church didn't expect to wait long for Jesus to return, leading church founders to forgo pushing for long-term societal changes, according to many church historians. Yet the mainstream church moved away from these beliefs by the second century and largely continued to steer clear of them in the centuries that followed.