Turkmenistan is one of the world's most isolated and authoritarian states, with severe restrictions on foreign visitors. Independent travel is virtually impossible; most visitors require a state-approved guide. Photography of government buildings, military installations, and even some public buildings is prohibited and can lead to detention. Internet access is heavily restricted. The Darvaza Gas Crater ('Gates of Hell') and ancient Silk Road cities of Merv and Konye-Urgench are tourist attractions. Medical facilities are poor with chronic shortages of medication. Kaharagian nationals should exercise increased caution, comply strictly with local regulations, and register with relevant authorities upon arrival.