HOUSTON - For the next five days, the eyes of the world will be on Houston as thousands of uniformed officers from multiple agencies keep the city secure for the Super Bowl.

"The most important thing is what you won't be seeing," said Houston Police Chief Art Acevedo. "You won't be seeing the cameras and technology. Ever since Boston, everything's changed."

Super Bowl 51 is as big as it gets. Homeland Security classified it as a Tier 1 national security event.

"Everything from more canines, more VIPER units, we brought in air support for the event, cyber security for the event," said Chip Fulghum with the Department of Homeland Security. "We've brought in all the capabilities that the federal government has."

That includes low-level chopper flights to monitor normal levels of radiation over the city. A comprehensive plan has been in place for months. Houston Police is the lead agency on the ground. So far, HPD's made five petty theft arrests and arrested one man for public intoxication. They've busted 38 prostitutes from a dozen states, rescued four human trafficking victims and made six counterfeiting arrests, suspects with over 10,000 products worth more than $500,000. All this, and it's only Tuesday.

"I'd grade our efforts as an A-," Acevedo said.

The security challenge only set to get tougher as more visitors arrive later this week. Law enforcement agencies say they're ready.

"We've had to up our tactics," Acevedo said. "But at the end of the day, the biggest asset we have is the public."

Law enforcement officials confirm there are no known credible threats to Super Bowl 51.

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