It’s happened before. A stadium packed with fans targeted by terrorists in Paris.
Now, new potential targets like the biggest game in college football, the 2016 National Championship game and other bowl games are headed to the Valley.
"We have been preparing for those types of scenarios, we've prepared for those types of scenarios,” said Kevin Kalkbrenner with the Department of Homeland Security in Phoenix.
Tuesday was training day for everyone from fire and medical to local police and the FBI.
Agencies worked together on a table top exercise
"There isn't anybody in this room, that doesn't have a role in one of those exercises and they are going to step up!” said Kalkbrenner
Agency coordination is key. Homeland Security says local first responders are even better prepared following the lessons learned from the Super Bowl in Glendale held back in February.