However, over 500 cities and areas in China are open to visitors without special travel permits, including most major scenic and historical sites. Special permission to visit any of the closed areas must be obtained from the region's public security bureau. Occasionally, visitors have been refused admission or had difficulty entering Tibet from Nepal. Avoid this road during the monsoon. Conditions in Tibet are primitive, and travel there can be particularly arduous.
Medical facilities are practically nonexistent.
Many otherwise healthy visitors to the high altitude areas may suffer severe headaches, nausea, dizziness, shortness of breath, or a dry cough. These symptoms usually disappear after a few days of acclimatization. However, if symptoms persist, sufferers should descend to a lower altitude, or seek medical assistance. Visitors with respiratory or cardiac problems should avoid such high altitudes. Consult a physician before making the trip.