Somewhere on the southern edge of Greece, on the island of Rhodes, a tall man with a sunburned face and a body as if sculpted by centuries of salt and wind stood at the helm of a little, ridiculous-looking steel boat called Yellow Submarine, advertising rides to children. Having missed all the other regular ferries, I decided to board it. 'I came this far,' he said with a grin, 'because I'm escaping from my wife.' Then he turned to my Ukrainian friend, who fears boats but not Russian bombs, as she froze at the dock while six-year-olds jumped aboard. The captain caught her hesitation, pointed...