SIOUX CITY -- Colon cancer isn't pretty.

Running your fingers across angry-looking, dark red polyps and cauliflower-like growths, you know this isn't something you want growing inside you and will do whatever it takes to prevent it.

That's what the folks who created the Colossal Colon hope, and it's one of the reasons Mercy Medical Center brought the 40-foot-long, 4-foot-high fiberglass replica of the human colon to Sioux City.

"It takes a funny look at a serious subject, a subject most people don't want to discuss, and makes it discussable," said Sheryl Sextro, a Mercy grant writer who dressed up as a polyp at the exhibit.

Through Saturday, the public is invited to the Sioux City Convention Center to crawl through the model and experience what doctors see when they perform colonoscopies. When Mercy obtained a Wellmark Foundation grant to bring the Colossal Colon here, the goal was to break down the trepidation people have about colonoscopies and show them the nasty conditions a regular colonoscopy can catch before it's too late.

"The whole purpose is to educate our community about the prevention of colorectal cancer," said Amy Slevin, director of clinical program development at Mercy. "The thing we want people to know is that the biggest symptom ... is no symptom. You could have this and not know it."

Nationwide, colorectal cancer is the second leading cancer killer, taking the lives of more than 50,000 Americans each year. Siouxlanders run a higher risk of the disease. According to information set up at the display, the U.S. average is 53.1 cases per 100,000 people. Iowa, Nebraska and South Dakota are all above that number, which reaches as high as 81.5 cases per 100,000 in Plymouth County, Iowa.

Seeing the numbers and then going through the Colossal Colon was an educational experience, said Mollie Gross of Sioux City, who toured the exhibit Tuesday morning with her nursing class from Western Iowa Tech Community College.

"You hear about stuff like this. It helps to see it and touch it," Gross said. "To draw people's attention to it and have a display ... it gets people to talk about it."

In addition to cancer, the Colossal Colon depicts noncancerous conditions such as normal polyps, Crohn's disease, diverticulitis and hemorrhoids. Windows along the outside allow you to see the conditions if you don't wish to crawl through the exhibit and feel them from the inside.

Again, they're not pretty. Slevin said she hoped that people will elect to overcome their apprehensions about colonoscopies -- having a tube inserted into their colons -- and have regular exams that can detect early signs of cancer and lead to prevention of those ugly conditions. A colonoscopy, recommended for everyone age 50 and older, is often the only way to detect some of the symptoms of colon cancer.

"We hope to have people feel this is an easy thing to do for my health. This could save my life," Slevin said.