Turkmenistan

Turkmenistan is one of the most isolated and enigmatic countries on Earth. Occupying a vast sweep of the Karakum Desert north of Iran and west of Uzbekistan, it sits on enormous natural gas reserves that rank among the largest in the world. Its capital, Ashgabat, holds the Guinness World Record for the most white marble-clad buildings in the world - an eerily pristine city of gleaming towers, golden statues, and wide empty boulevards that feels like a science fiction movie set. Very few tourists visit, and those who do discover a country that is genuinely unlike anywhere else.

But Turkmenistan's real treasures predate the marble. The ancient city of Merv was once one of the largest cities in the world, a Silk Road metropolis that rivaled Baghdad and Cairo before the Mongols destroyed it in 1221. The ruins of Nisa, capital of the Parthian Empire that defeated Rome, sit just outside Ashgabat. And then there is the Darvaza Gas Crater, known as the Door to Hell - a 70-meter-wide pit in the desert that has been burning continuously since Soviet geologists set it alight in 1971, its flames visible for miles across the empty landscape at night. Turkmenistan is strange, restricted, and genuinely unforgettable.