The paddy fields of the lowlands are immensely fertile, fed with nutrients by the erosion of topsoil from the nearby hills, and producing two or three rice crops a year. A complex system of irrigation channels and low mud walls to trap the water in which the young rice grows produces a patchwork of vivid greens, broken only by the scattered villages of bamboo and teak and the extravagant colours and designs of Buddhist temples. In the fields, teams of farm workers can be seen planting, weeding or harvesting the rice, assisted by the water buffaloes, giant but placid grey or pink beasts ubiquitous to South East Asia.

The hills which look down on these fertile lowlands are a different world. They are naturally covered in dense tropical forest, with a huge number of species of trees. At low levels the trees are small and spindly, losing their leaves in the long dry season. At higher altitudes, where the rainfall is greater and the temperature lower, the size, density and lushness of the forest increases, culminating in cloud forest above 2000 metres, where the trees are covered in a thick flora of epiphytic mosses, ferns and creepers. It is at these higher altitudes that the dazzlingly beautiful and highly prized orchids can be found - perhaps the most familiar symbol of northern Thailand.

The predominant limestone rock leads to the formation of a myriad of caves and potholes, many still undiscovered and unexplored. Home to bats and cave swifts, they are sacred places to the Thais, who for hundreds of years have decorated them with shrines and Buddha images. Many contain artefacts from earlier civilizations, still a puzzle to archaeologists.