"In Stamboul, remember, across the Galata from Pera. I had finished the flight of marble steps and entrance of the Valedée, and was looking around for another subject, when a Turk with a green scarf around his fez (that showed he'd been to Mecca), who had been keeping off the crowd while I painted, offered to carry my trap to the Mosque of the Six Minarets up in the Plaza of the Hippodrome. A man who has been to Mecca is generally to be trusted, so I handed him my kit and followed his lead. On the way to the plaza he stopped beside a low wall and pointed to an opening in the ground. I looked down and saw a flight of stone steps. "'This is not for the Effendi to paint,' he said, 'but it is something for him to see. It is the great underground cistern where the water was kept during the sieges.' "That suited me to a dot--caverns always appeal to me--and down I went, followed by the green fez. Down, down, down, into a big vaulted chamber, the roof supported on marble columns running back into the gloom, only the nearby ones in relief where the light from the opening above fell upon their white shafts, very much as a forest looks at night when a torch is lighted. Stretching away was a dirt floor, uneven in places, and away back in the half-gloom I could make out the surface of a great pool. Now and then something would strike the water, the splash reverberating through the cavern. "When my eyes became more accustomed to the darkness I could see men moving about, dragging ropes, and beyond these a dull light, like that from a grimy cellar window. This, the Turk said, was the other exit, the one nearest to the Mosque of the Six Minarets; the men, he added, were rope-makers; some of them lived here and only left the cisterns at night, as the daylight blinded them. So I followed on, the Turk ahead, my kit in his hand.