Potala Palace is a former palace-fortress, an example of a type of architecture called 'dzong', dating back to the 17th century.
Any trip to Tibet has to go through Lhasa. It is worth staying several days in the capital to sound the country out, and also to visit monasteries within a range of nine miles. What should you see in Lhasa? Do not begin by going up to the Potala, the Dalai-Lamas' palace, in order to get used to the altitude. First of all, visit the old town on foot to discover the Barkhor, a type of ritual alleyway, followed by pilgrims from all over Tibet, each wearing the colourful costume from their area and turning their prayer wheel. This circular road, around the Jokhang, has to be followed clockwise (it is lined with stalls). The pilgrims then reach the Jokhang, the most venerated sanctuary of Tibet, in a state of extreme fervour, and offer their ceremonial scarves there, together with yak butter for the lamps. You can visit this place, which is only open in the morning, for around CNY 25. Getting there early allows you to have a superb view over the Potala and the plain. Note that access to all the important temples and monasteries has to be paid for. The market, with its stalls of meat, vegetables, and cereals, is a short distance away. See the Muslim market and its little restaurants around the mosque, which is close by. The Potala Palace (390 feet high), which is emblematic of Tibet, was built from 1645 and took fifty years to build. Then, each Dalai Lama provided their contribution and its fittings. Chapels, halls, grottoes, large rooms and staircases follow on from each other, and you have to devote several hours to gently walking around the sacred place, which can only be visited on Monday and Thursday mornings. Information and access tickets (around CNY 50) must be obtained from big hotels or agencies. Photos are strictly prohibited. Ani Sangkoung, near the mosque, is a 15th century nunnery. In use again, it harbours interesting frescoes. The Ramoche temple, to the north of the old town, dates from the 7th century and holds some five hundred monks (see its magnificent prayer wheels). The Norbulingkha (garden of the Precious Stone) is a large park at the western foot of the Potala. It has four summer palaces, built by the Dalai Lamas, and another that was completed in 1956. You can take several other excursions from the capital lasting from one to three days, preferably in a hire car with driver.