In the early, heroic days of archaeology, it was invariably the ambition of those who headed out to the Levant, armed with pick and shovel, to track down wonders that they had read about in classical literature or the Bible. We tend to remember the successes. To this day the paradigm remains Heinrich Schliemann, whose faith in the historicity of the Trojan War led him to identify the walls of Troy and to gaze on what he described as the face of Agamemnon. Less well remembered are the failures. In 1898, when a German archaeologist named Robert Koldewey arrived in Babylon, he was keen to emulate Schliemann and secure further funding for his excavations by bringing to light the city’s long-lost landmarks. Of these, the most famous and romantic proved the most elusive as well. Despite almost two decades of searching, Koldewey and his team never succeeded in identifying the location of any hanging garden in Babylon. Nor has anyone since.

The disappointment has never quite lifted. The Hanging Garden was perhaps the most wondrous of all the seven wonders identified by classical writers as global must-sees. Shimmering on the easterly extremity of Greek and Roman horizons, it was a marvel fashioned as much out of flowers and foliage as stone,