BANLUNG, Ratanakkiri province Paved roads peter out long before this ramshackle town emerges in the jungle. Beyond it are crater lakes, sun bears and hunter-gatherer hilltribes that are only now starting to interact with the outside world. Together they make up one of the last frontiers of Asian adventure travel, the vast province of Ratanakkiri. For decades, the war-torn region of waterfalls and winding jungle paths held a strange allure for travelers, mainly because it was so cut off from the outside world. The trip, by truck and canoe, would take days and sometimes weeks, depending on the weather. But as Cambodia has opened more widely to the outside world – it expects some two million tourists in 2009 – its northeastern jungles have started to open up, too, even to luxury travelers. Authorities have extended paved roads to within about 100 km of Banlung, the provincial capital, and new construction is expected to cover the last leg sometime over the next several years. That has cut travel time from Phnom Penh to about 10 hours by car and led to significant upgrades in food and lodging. The government is stepping up efforts to promote Ratanakkiri, touting it as the “Wild East” in marketing campaigns. Officials cite the region’s ethereal landscapes and its wildlife, including exotic birds, elephants and possibly kouprey, the mysterious and rare wild forest cow believed to live in northern Cambodia and surrounding areas. Commercial flights used to land in Banlung but were discontinued earlier this decade due to safety concerns; now the lonely airstrip it more commonly used for motorbike races. Officials are planning to upgrade the airstrip and restore the terminal to once again receive commercial flights. Cambodia has undergone a massive travel boom in recent years, and international tourists have overwhelmed the country’s more-famous destinations, like Angkor Wat, the renowned complex of ruins further to the west. (Although only about 120 km away, Angkor Wat is exceptionally difficult to get to directly from Banlung because of the bad roads.) Many jaded travelers find they prefer a sparsely populated redoubt like Ratanakkiri because it offers a better sense of the way Southeast Asia used to be. Not far outside Banlung is Yeak Lom, a serene, circular crater lake hidden in the jungle. Depending on whom you ask, the lake is either a few thousand or 700,000 years old. Either way, it feels timeless, hemmed in by dense forest under a wide blue sky. Cambodian families and foreign visitors gather there throughout the day. Residents have built a wooden deck along the water for lounging, and vendors sell soft drinks and snacks from a clearing nearby. Swimmers can float out into the cool waters, surrounded by nothing but jungle. In the evenings and mornings, a silence settles over the lake that makes it seem otherworldly. Ratanakkiri offers the opportunity to visit some of region’s ethnic tribal groups, including the Cambodian Kreung and Tompuon, with the help of guides hired through Banlung guesthouses. Residents of these hill communities are quickly adopting Western habits, but they retain their own dialects and some of their own customs, including the worship of nature spirits. Tribal cemeteries, which are often situated in remote jungle areas and best reached by boat or canoe, have carved totems that look like pre-Columbian artifacts. Village residents generally don’t mind visitors in the cemeteries, but tourists should go only with a guide and a tribal member, and they should show all proper respect, including refraining from touching totems.