The Baekdu Daegan mountain range twists its way more than 1,000 miles down the length of the Korean Peninsula, from the sacred peak of Baekdusan on the North Korea-China border to Jirisan in central South Korea. Today, it is choked off by landmines and barbed wire at the demilitarized zone, but once, it was considered the "spine of the nation" -- a source of spiritual energy and strength for the Korean people. At least 75 percent of the Korean Peninsula is covered by mountains, and long before the country was divided -- first by Cold War politics and then by a war -- Koreans shared a reverence for the power of these peaks. Mountains are prominent in Korean art and literature. Koreans practicing animism once paid homage to mountain spirits to ensure them safe passage on their journeys. Today, the lyrics of both countries' national anthems still sing the praises of Baekdusan, or Great White Mountain, the sacred peak said to be the place of ancestral origin for the Korean people. Over the past two years, New Zealand native Roger Shepherd was granted rare permission to spend more than two months in the mountains of North Korea as part of his efforts to document the Baekdu Daegan as one ridge, north and south. Shepherd has made three trips to the country, during which he covered more than 6,000 miles and visited more than two dozen mountain peaks. "These days we see Korea as divided," Shepherd says. The Baekdu Daegan system, he tells FP, helps remind us that geographically, Korea is still one entity with a shared history and a shared culture as mountain people. I hope my work can reinvigorate that mindset. These are the revealing photographs from his time in the country known to most of the world as "one of the most closed and secretive nations on earth." Above, farmers catch a lift across the Saepo-gun plateau below the Baekdu Daegan ridge in Kangwondo, DPRK. Above, Cheonji lake, or Heaven Lake, at the peak of Mt. Baekdu, in the northern part of North Korea. Baekdusan is the highest mountain on the peninsula, at 2,750 meters tall, and is where the Baekdu Daegan ridge begins. The mountain -- a dormant volcano -- is considered sacred to all Koreans: the place where, according to legend, those who would go on to become Koreans first descended to earth. In North Korea, the mountain range has become a place to be valued for its resources, Shepherd says. It's frequented by skilled woodsmen, hunters and foragers looking for timber, meat, and herbs -- people who, Shepherd says, "share a unique relationship with nature, that is rarely seen these days in modern consumerist nations." The Baekdu Daegan range is considered the source of energy and life on the peninsula, in part because its mountains are the point of origin for almost all of Korea's major rivers. Above, loggers send timber downstream near Dacheonpyeong-ri near the Baekdu Daegan in Eunheung-gun, Yanggangdo. With elevations ranging between 700 and 2,000 meters, the Kaema-gowon plateau in the northern central province of Yanggangdo is known as the "roof of Korea." Local people there live a subsistence lifestyle: Rice cannot grow in these altitudes, so their main crop is potatoes and other vegetables, supplemented by goats, sheep, and cattle. Above, farmers on the Kaema-gowon plateau. A shepherd takes his goats to pasture up on the mountains in Sinyang-gun, Pyeongannamdo. Above, a monument to 'Songun,' or the DPRK's military-first policy, in the small town of Kim Hyong Gwon, located on the Kaema-gowon plateau in Yanggangdo, DPRK. This town, once known as Pungsan, was renamed Kim Hyong Gwon as a tribute to Kim Il Sung's uncle, a celebrated revolutionary in the North who fought against the Japanese in the early 20th century. In the North, Shepherd says, part of the Baekdu Daegan's fame now comes from its former role as a refuge for Korean independence fighters -- including North Korea's founder, Kim Il Sung. Relics from that era, including old secret hideout camps and trees carved and inked with revolutionary slogans, are still preserved as memorials on the mountain slopes. A young mother and baby on a bike near Bukdaebong mountain, Singyang-gun, Pyongannamdo. "The squeaky spokes of the bicycle were the only sounds I heard as I sat on the side of the road in the tranquil silence of the Korean countryside," Shepherd says. The forests in North Korea's northern regions -- particularly on the Baekdu Daegan -- remain in a primal, untouched state, Shepherd says. "These areas were always seen as wild lands," he said. One of the guides living on Korea's holy Baekdusan mountain. Walking back down from Cholongsan mountain on the Baekdu Daegan through maize fields located on the Jungheung-ri plateau, Pyonggannamdo. The group's accomodations, near Bujeon-ryeong, Hamgyeongnamdo. The man pictured eating lunch is Hwang Sung Chol, secretary-general of the New Zealand Korea Friendship Society, who helped arrange Shepherd's trip. "Often, my journeys saw us taking breaks by the seaside to recuperate our bodies and minds," Shepherd says. Here, a brother and sister play on a beach called Hwajin-po in Goseong-gun, Kangwondo. Railway tracks built by the Japanese in the early 20th century deliver coal and other minerals throughout the Kaema-gowon plateau region. The border town of Hyesan, near Mt. Baekdu. The ridge rising in the background is part of China. A cinema in the small town of Eunheung-gun, in the foothills of the Baekdu Daegan in Kaema-gowon, Yanggangdo. My awesome forest service guide Pak Geum Chol for the big, 2,309 meter mountain of Duryusan in Baegam-gun, Yanggangdo province. On our ascent up Duryusan, someone had filled the majority of our plastic water bottles with acorn soju (distilled wine) instead of water ... By chance, a brother and sister were effortlessly passing over the mountain and led us to a hidden spring where we replenished our bottles. Above, the Baekdu Daegan range looms over a village in Sudong-gun, Hamyeongnamdo. Young cadets of the Korean People's Army take shelter under a parasol in the larch pine forests of the Paektu-gowon plateau. Above, a farmer and his cow on the Kaema-gowon plateau. These cows, called Hanu, are indigenous to Korea. Those that live on the northern plateaus are said to have shorter legs, due to the altitude. A farming community in the Kaema-gowon plateau, Yanggangdo. Shepherd with his team on the summit of Duryusan mountain in Cheonnae-gun, Kangwondo. "What was supposed to be a one-hour hike turned into an eight-hour ordeal," as the team struggled to get up the steep mountain, Shepherd says. I nicknamed my guide [far left] Mr. Han Shigan, meaning 'Mr. One-Hour.' Shepherd's travels were focused on the mountains themselves, and not the people and culture of North Korea. Still, he says, the people he encountered during his trips were "a highlight." He was frequently helped out by locals along the way -- whether it was through offers of accomodation, or guides who led the way up some of the trickiest terrain. North Korea is often treated as a strange, mysterious place, Shepherd says -- somewhere to be gawked at by the rest of the world. But these pictures provide a glimpse at a side of North Korea -- its natural beauty -- outside of the mass rallies and blustery politics emanating from Pyongyang that form so many peoples' main impressions of the country. "Mountain photography doesn't generate controversy, of which there is plenty on the peninsula," Shepherd says. But through the study of Korea's mountains, it's still possible to come to a more complete understand of the peninsula's people -- north and south -- and what they represent. "The Baekdu Daegan still holds deep rooted importance to the Korea people" that goes deeper than the ideologies keeping both halves of the Korean nation apart, he says. It goes back into the very DNA of the Korean people: born from mountains.