A mesa is an isolated, flat-topped elevation, ridge or hill, which is bounded from all sides by steep escarpments and stands distinctly above a surrounding plain. Mesas characteristically consist of flat-lying soft sedimentary rocks capped by a more resistant layer or layers of harder rock, e.g. shales overlain by sandstones. The resistant layer acts as a caprock that forms the flat summit of a mesa. The caprock can consist of either sedimentary rocks such as sandstone and limestone; dissected lava flows; or a deeply eroded duricrust. Unlike plateau, whose usage does not imply horizontal layers of bedrock, e.g. Tibetan Plateau, the term mesa applies exclusively to the landforms built of flat-lying strata. Instead, flat-topped plateaus are specifically known as tablelands.
Lhasa, referred to as "La" for short, is the capital of China's Tibet Autonomous region, an international tourist city with plateau and ethnic characteristics, the political, economic, cultural, scientific and educational center of Tibet, and the holy place of Tibetan Buddhism. Located in the middle of the Tibetan Plateau, north of the Himalayas, 3650 meters above sea level (to prevent endogenous oxygen deficiency), is located in the valley plain of the middle reaches of the Lhasa River, a tributary of the Yarlung Zangbo River, which flows through it and flows into the Yarlung Zangbo River in the southern suburbs. Lhasa has sunny weather all year round, with little rainfall, no severe cold in winter, no heat in summer and pleasant climate. The sunshine time of the whole year is more than 3000 hours, which is known as "Sunshine City". Lhasa is rich in all kinds of resources, which has obvious resource advantages compared with other prefectures and cities in the country and the autonomous region. As the first batch of famous historical and cultural cities in China, La