By headcount, the North Korean military is one of the largest in the world. And much of its power relies on how it is seen . National Geographic's David Guttenfelder has the rare credentials of being a western photographer allowed inside the so-called Hermit Kingdom. His mobility in the country is often restricted, but not as much as you’d think, especially when it comes to the military.

“You see them everywhere, they’re not just the country’s defense, they’re part of North Korea’s entire identity,” he says. Soldiers do development projects, they build infrastructure, and they keep life in Pyongyang running smoothly under the country’s regime. Guttenfelder’s access also included invitations to the annual Mass Games performance and the highly choreographed military demonstrations of goose-stepping soldiers and artillery on parade. Everyone at the event has a role to play, including the spectators, who use color flip-books to make grand mosaics from the stands. The images are usually tributes to the country’s leaders, or simply, the military at large.