If you see an inordinate number of firefighters rushing around Las Vegas this week, do not be alarmed. It’s all part of the Scott Safety Firefighter Combat Challenge, an annual competition which wraps up months of challenges across the nation at the Stratosphere.

The competition features hundreds of firefighters from more than 15 countries, including New Zealand, Germany, Argentina and South Africa, and this week’s activities determine seeds for the finals on October 26 and 27.

It’s grueling competition of the highest order. Clad in full gear, pairs of firefighters will compete head to head in a linked series of five tasks, including rescuing a 175-pound “victim,” dragging hoses, hoisting, chopping and climbing a five-story tower, all while showing the viewing public the everyday demands of the job.

If you’ve ever watched this event on ESPN, you know how intense it can be—real reality entertainment from real-life heroes.