(L-R) Drew Miller and Kacey Dawson walk across the property of a survival camp, armed with weapons, in central Colorado, U.S., December 9, 2019.

Supplies including mattresses, toilet paper, and blankets are stacked to the ceiling in an underground shelter at a survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

Supplies including mattresses, heaters, and blankets are stacked to the ceiling in an underground shelter at a survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

Drew Miller, manager and co-founder of Fortitude Ranch, poses for a portrait at his survival camp in central Colorado, U.S., December 9, 2019.

Kacey Dawson, assistant manager of a Fortitude Ranch camp, stands armed in a lookout tower at a survival camp in central Colorado, U.S., December 9, 2019.

Drew Miller carries an assault rifle at a survival camp in central Colorado, U.S., December 9, 2019.

The exterior of a survival camp operated by Fortitude Ranch in central Colorado, U.S., December 9, 2019.

The exterior of a survival camp operated by Fortitude Ranch in central Colorado, U.S., December 9, 2019.

Emergency food is stocked in an underground bunker at a survival camp in southern Colorado, U.S., December 9, 2019.

A mountain range near a survival camp in southern Colorado, U.S., December 9, 2019. P

The interior of a Colorado survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

The interior of a Colorado survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

Drew Miller climbs up the ladder of a lookout perch at a survival camp in central Colorado, U.S., December 9, 2019.

The interior of an underground shelter at a survival camp in southern Colorado, U.S., December 9, 2019.

A weapons cache is seen in the basement of a survival camp in southern Colorado, U.S., December 9, 2019.

Drew Miller, manager and co-founder of Fortitude Ranch, poses for a portrait at his survival camp in southern Colorado, U.S., December 9, 2019.

Kiki Bandilla, who produces Denver’s Self-Reliance Expo, poses for a portrait in Parker, Colorado, U.S., December 10, 2019.

A view through the window of a lookout tower at a survival camp in central Colorado, U.S., December 9, 2019.

Kacey Dawson stands inside the living room of a survival camp in central Colorado, U.S., December 9, 2019.

Emergency food is stocked in an underground bunker at a survival camp in southern Colorado, U.S., December 9, 2019.

The interior of an underground bunker at a survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

(L-R) Kacey Dawson and Drew Miller stand inside the living room of a survival camp in central Colorado, U.S., December 9, 2019.

An American flag flies outside a survival camp in central Colorado, U.S., December 9, 2019.

(L-R) Drew Miller and Kacey Dawson stand on a lookout perch holding weapons at a survival camp in central Colorado, U.S., December 9, 2019.

The exterior of a survival camp operated by Fortitude Ranch in central Colorado, U.S., December 9, 2019.

(L-R) Drew Miller and Kacey Dawson stand outside a survival camp in central Colorado, U.S., December 9, 2019.

The interior of a Colorado survival camp called Fortitude Ranch in southern Colorado, U.S., December 9, 2019.

Drew Miller, manager and co-founder of Fortitude Ranch, stands near a weapons cache at his survival camp in southern Colorado, U.S., December 9, 2019.