Cities have always been isolated from something – from epidemics, enemies and not only. Initially, the cities were created in such a way that it could be quickly closed for defense and protection, but even now there are many settlements that are difficult to access for any reason.

Mecca and Medina
Holy Muslim cities of Saudi Arabia: entry for representatives of another religion is prohibited. You can get here only with a group of Muslim pilgrims from Russia. Here is the main shrine - the Kaaba, a huge cube in the largest mosque Al-Haram. Here lived and died the Prophet Muhammad, near his house - a dome, and near Medina - the first Islamic mosque Al-Quba.
Pyongyang
The capital prohibits entry to Americans, South Koreans, journalists. Other tourists can come, but only in small groups. A visa is requested at least one month before visiting the country. On the territory of North Korea, a tourist does not have the right to move somewhere without a guide. But now at least do not take the phones at customs, thank you.
Mogadishu
For more than 20 years, there has been a civil war, so Mogadishu is the most dangerous capital, and Somalia occupies the second line of the list of the most closed countries, second only to North Korea. For the year there is a maximum of 18 thousand foreigners, and tourists among them are negligible.
San Pedro Sula
It is considered the most dangerous city on earth: here the highest level of crime, cartels dominate. San Pedro Sula is located 60 km from the Caribbean Sea.
Ashgabat
Turkmenistan bears the title of one of the most isolated countries. For example, there is an unpredictable and semi-preclusive visa policy. A visa can be obtained only in the Ministry of Foreign Science, all this is accompanied by a heavy bureaucracy. Once there, you are obliged to move with a guide-sexot, and the choice of hotels for accommodation is extremely limited.