Of all the fascinating sights on my recent trip to Holland and Belgium, this control tower in Rotterdam harbor stands out. Several of these towers control traffic in and out of the busiest harbor in Europe.

Imagining a job in one of these structures brought back the memory of standing over a warm air register in my house as a child as I watched out the window, fingered the controls of a wall-mounted drying rack and mouthed instructions as if directing trains in and out of a busy railyard.