Ringed by mountains which proverbially made the journey here "harder than the road to heaven", SICHUAN and CHONGQING stretch for more than a thousand kilometres across China's southwest. Administratively divided in 1997, when Chongqing Municipality was carved off the eastern end of Sichuan Province , the region has long played the renegade, differing from the rest of China in everything from food to politics and inaccessible enough both to ignore central authority and to provide sanctuary for those fleeing it. Recent divisions aside, Sichuan and Chongqing share a common history, and the area splits more convincingly into very different geographic halves: a densely populated eastern plain, and a mountainous west, emphatically remote.

In the east, peaks surround the fertile Red Basin , home to most of the region's 110 million residents and one of the country's most densely settled areas. One of Han China's "rice bowls", a subtropical climate and rich soil conspire to produce endless green fields turning out three harvests a year, a bounty which has created an air of easy affluence in Chengdu , Sichuan's capital, and the southern river towns of Zigong and Yibin . Elsewhere, visitors have the opportunity of joining pilgrims on Emei Shan in a hike up the holy mountain's forested slopes, or of sailing down the Yangzi from Chongqing , industrial powerhouse and terminus of one of the world's great river journeys. You'll also find that the influence of Buddhism has literally become part of the landscape: most notably at Leshan , where a giant Buddha sculpted into riverside cliffs provides one of the most evocative images of China; and farther east at Dazu , whose marvellous procession of stone carvings has miraculously escaped desecration.

In contrast, the west is dominated by densely buckled ranges overflowing from the heights of Tibet; a wild, thinly populated land of snow-capped peaks, where yaks roam the treeline and roads negotiate hair-raising gradients as they cross ridges or follow deep river valleys. To the northwest, the mountains briefly level out on to the high-altitude Aba Grasslands , while south the ranges run lower but no less severe, cloaked in the impenetrable greenery of cloud forests. Occupied but never tamed by Han China, and often excruciatingly difficult to traverse, the west's biggest appeal is its very inaccessibility. Nearest to Chengdu, there's a chance to see giant pandas at Wolong Nature Reserve , while travelling north towards Gansu takes you through ethnic Hui and Qiang heartlands past the vivid blue lakes and beautiful mountain scenery around Songpan and Jiuzhai Gou . Due west are the fringes of Tibet, including Hailou Gou Glacier lying in the foothills of Gongga Shan , Sichuan's highest peak, and predominantly Tibetan towns such as Kangding .

New roads and better vehicles mean that getting around all this is not always the endurance test it once was, though those heading westwards still need to prepare for unpredictably long and uncomfortable journeys. Rail lines are restricted by geography - construction was such a monumental task that Chengdu was linked to the national network only in 1956 - and most people use the train only for travel beyond regional borders; the most useful internal route is along the Xi'an-Kunming line, which runs southwest from Chengdu via Emei Shan and Xichang. As for the weather , expect warm and wet summers and cold winters, with the north and west frequently buried under snow for three months of the year.