The moment the ferry crossing the western end of the Mediterranean pulled away from the wharf on Spain’s southern edge, I felt something slip away. Not the sway of the vessel — something finer than that. As if the quality of gravity itself had shifted. The engine’s vibration traveled up my spine, announcing that I was no longer bound for anywhere on the Eurasian landmass. Algeciras harbor receded, and I entered the space we call the Strait of Gibraltar.

The cabin interior was strangely mundane. Torn vinyl seats, unappetizing espresso sold at the kiosk, and some receipts lying on the floor. I’d expected something sublime for the cross-border, but reality offered only a dull two-hour passage. In the next seat, a young woman soothed her infant. Moroccan, perhaps. For her, this was a homecoming; for me, arrival at somewhere new. We rode the same vessel, yet traveled different journeys. By the window, an old man gazed at the water with unfocused eyes. Perhaps he’d crossed this strait hundreds of times in his life.

The first thirty minutes aboard felt surprisingly long. The sea remained the same gray, and through the porthole I could still make out land. When I rose to use the restroom, I passed men speaking Arabic in the corridor. Then at some point, time suddenly compressed. We must have been nearing the strait’s narrowest passage. Spain to the right and ahead, Morocco to the left and beyond. Only a few dozen kilometers between them. Two continents facing each other at such proximity. A child pressed against the window, pointing at something. What lay in that direction — Africa, Europe, or the currents flowing between?

The quality of light around us seemed to shift. Whether it truly changed, I couldn’t say. Something within me insisted that Spain and Morocco must differ in every way. Yet the color of the sea did not change. Still gray as before. No dramatic visual transformation anywhere.

An announcement came over the speakers. Spanish, then Arabic, then English. Only the Arabic I couldn’t understand at all freed me from the burden of language.

Countless people have crossed this strait before me. Ancient Phoenician merchants, Islamic conquerors, the pursued, the hopeful. And tourists. I was about to join the tail end of that procession.

The Moroccan city of Tangier came into view. At what moment would I actually arrive there? When the ferry docked? When I took my first step on land? When I met someone’s gaze on shore? Or when I sensed the scent and sound of that place?

The ferry slowed. The engine’s pitch changed. People began to stand, reaching for their bags. I did the same. The heavy, dry metallic sound of the gangway being lowered traveled through the vessel as vibration.

I joined the line, inching forward. One step, then another. Which step would cross the boundary — I still couldn’t tell.

I met the eyes of a port official. He looked at me and seemed to register something. To him, I was just one more face from Europe, perhaps the hundredth today. To me, he was the first person I’d locked eyes with in an unfamiliar port. I could register nothing about him. Communication is always asymmetric on the road.

I descended the gangway. My feet met hot concrete. I couldn’t immediately recognize where I was. Beyond the ambiguous boundary called the Strait of Gibraltar, a journey through the African continent was about to begin.