Mardin rewards wandering without agenda. Start at the Sultan Isa Medrese — the rooftop terrace gives the best overview of the city and the plain. Walk east along Cumhuriyet Caddesi through the old city to the Kasımiye Medrese. The Church of the Forty Martyrs and the Great Mosque are both worth entering. The Mardin Museum provides essential context for the layers of history on show in the streets. The essential excursion is to the Mor Hananyo Monastery five kilometres east — one of the oldest functioning Christian monasteries in the world.