The Basilica Cistern, Istanbul

The Basilica Cistern in Istanbul is an underground wonder, an engineering marvel, dating back to the 6th century.

Guidebook photographs show serried columns eerily surrounded by water, echoed in their watery reflections. The water had been drained, unfortunately, when we were there, for repairs, so some of the magic was missing, at least to my eyes, but the place was impressive, nonetheless, a kind of netherworld, the sort of place you imagine might be a crossing-point to the world beyond this one.

A solitary oarsman emerging out of the gloom, offering to transport you across.