When I first visited Diyarbakir a decade ago, I only saw the bus station. The ancient Mesopotamian city was embroiled in fighting between the Turkish military and Kurdish separatists. I left as swiftly as I’d arrived.

Things have changed, and Diyarbakir’s streets are now peaceful.

Inside the Mesopotamia Express (Photo: Provided)

Ringed by 6km-long Roman walls, it has a history stretching back 9,000 years and the 11th-century grand mosque is one of Islam’s holiest sites.

Diyarbakir is a dream for history-lovers, but also rail enthusiasts. It’s on the route of one of Turkey’s longest, yet little-travelled, train journeys. Every day, the Mesopotamia Express departs Diyarbakir Gar on its 1,051km journey north west to Ankara, Turkey’s capital, taking 23 hours. With seated tickets costing just 760 lira (£12) each way, it’s an absolute bargain.