A new sightseeing train service is whisking travelers across the vast Anatolian steppe and through Turkey’s eastern mountains to the northern plains of Mesopotamia, known as the cradle of civilization. Inaugurated in April by the government-run Turkish State Railways, the weekly Diyarbakir Express rides the rails for 653 miles from the Turkish capital of Ankara to the southeastern city of Diyarbakir. Ringed by impressive black basalt walls originally constructed in the 4th century, Diyarbakir’s history dates back thousands of years; today it’s a predominantly—and proudly—Kurdish city with a vibrant urban culture distinct from other parts of Turkey. Passengers on the 180-person-capacity train can watch the ever-changing scenery from the windows of their cozy sleeper cabins equipped with sinks and mini-fridges or while eating grilled meatballs (kofte) and other Turkish favorites in the dining car. Sightseeing stops allow for a few hours’ exploration around different stops on the roughly 24-hour journey in each direction. Traveling eastward from Ankara on Friday afternoon, riders disembark for three hours early Saturday morning in Malatya, home to the Bronze Age site of Arslantepe, where there are wall paintings that date to 3,000 B.C. The westbound return includes four hours in Elazig, where the hilltop Harput Castle has been surveying the landscape since the 8th century BC, and three hours on Monday morning in the former Seljuk stronghold of Kayseri, in the snow-capped shadow of the dormant volcano Mt. Erciyes. It’s just a taste of the rich offerings this lesser-visited region has in store.