Back in 1994, Leo Tanguma was working in his studio in the Lakeside Mall when a van full of people pulled up.

"And they weren't hostile," he recalls. "They asked a lot of questions." They wanted to know about all the different symbols in the murals that he'd been commissioned to make for the still-unopened DIA. "And I explained it like I explain it to everybody," the artist says. The first part of the environmental mural is about the ways that humans destroy nature and themselves through destruction and genocide. The second part is about humanity coming together to rehabilitate nature and revive their own compassion.

Tanguma likes to keep things simple. He may be left-wing, but he says he's not a liberal intellectual. He's a Christian who thinks of his murals as painted sermons, depicting the virtues of the poor and hardworking, and warning against the evils of greed and violence. Like many painters trained in the Mexican style of mural art, Tanguma gears his work to the street and all of its elements, everyone from businessmen and college professors to people like his parents, who were all but illiterate. The last thing Tanguma wants is for viewers to mistake his meaning.

The visitors stayed for more than an hour, looking around his studio, talking. One of the women asked Tanguma if the airport had told him what to paint. He remembers that, because he remembers how she said it. He told her no, that he was given no instructions on content. And then the visitors began to talk about how the United Nations was another conspiracy to take over the United States.

"How do you figure that?" he asked.

Before they left, they went to the back of their van and pulled out a thick, photocopied book detailing the U.N. conspiracy. They gave Tanguma the book. He knew where it was until about ten years ago, when he moved his studio from the strip mall to a modest house in Arvada where he lives with his wife.

Now that his art has become so central to a growing group of conspiracies, he wishes he could find it.