Merv, Turkmenistan: The Ruined Silk Road Capital You Need a Visa to See Ancient Merv is a 4,000-year-old UNESCO World Heritage Site in Turkmenistan’s Karakum Desert — five successive city ruins built next to each other across the millennia, including the Seljuk capital that was once the largest city on Earth, the Sultan Sanjar mausoleum, the Erk Kala citadel, and the corrugated mud-brick walls of Kyz Kala. Getting there requires navigating one of the world’s most restrictive visa regimes. Your complete 2026 guide to Merv, the Turkmenistan visa process, and the Silk Road archaeology circuit. Merv is the city that medieval Arab and Persian geographers called “the mother of the…