DENVER -- On the weekend of the Columbus Day holiday, a T-shirt is at the center of a long-standing conflict between those who celebrate the holiday and those who say it doesn't deserve to be celebrated.

The T-shirt had been for sale at the Colorado History Museum, but has recently been pulled off the racks.

The T-shirt features four Native Americans with guns along with the slogan: "Homeland Security. Fighting terrorism since 1492."

You can't buy it at the museum anymore, but jump over to the 16th Street Mall, and you'll find it at the Only in Colorado shop.

"We don't sell it because it's controversial. We pretty much sell it because it sells really well. It's one of our best-selling shirts in this store," said store employee May Joo.

In fact, in a store packed with T-shirts, it's the third best seller.

At the Colorado History Museum, visitor Jonathan Hagn learned that he would have to walk away empty-handed.

"I was told I couldn't buy it because they're not selling it," Hagn said.

The shirt was yanked off the gift store shelves after some found it offensive. The shirt hints to the premise that explorers such as Christopher Columbus were essentially "terrorists" when they invaded a land that had already been occupied.

Protesters to the Columbus Day holiday say that Columbus shouldn't be celebrated for discovering America because Columbus' "discovery" led to the oppression, degradation and deaths of hundreds of thousands of Native Americans.

Coincidentally, there are current exhibits at the museum featuring the history of the Italians and Native Americans. The gift shop owner said one complaint letter led to the store removing the T-shirt.

According to the company that prints the shirts, the history museum sold so many that they would have to order a new batch every week just to keep up with the demand. But that was before the controversy started.