1.

In a nowhere-stretch of Scotland’s western Highlands lies a town called Glenfinnan. It’s known as the site of an ill-fated 1745 Jacobite rebellion and more than one scene from the Harry Potter movies, where the protagonist and his ginger-haired sidekick, Ron Weasley, fly over and under the arches of a spectacularly scenic viaduct. The structure exists in real life as well, and was originally built for an elevated train line, still in use today.

I came into Glenfinnan over the same structure, with no plans for the day beyond simply getting there. I heard the Glenfinnan viaduct was something to see. I had the day off. So I hopped the line from Glasgow, where at the time I was launching the start and end of a career waiting tables.

I putzed around Glenfinnan for the morning, marveling at a glorious Catholic chapel on the bank of Loch Shiel. The body of water splinters from east to west across the land, which rises in bluffs and bumps for several thousand feet of evergreen, maroon sediment, and bare rock the color of wet pavement. At one end, a stout monument to the rebel Charles Edward Stuart, or “Bonnie Prince Charlie,” a Catholic fighting to take the British throne, soars against the backdrop of silver water.

After a lunch of gourmet-level fish and chips at a nearby bed-and-breakfast, I returned to the road leading up to the train station and nearly missed an overgrown track of access road that seemed to climb straight up the incline toward the viaduct. Who’s to stop me? I asked myself, and before I mustered an answer, found my feet making swishing sounds up the hill through the tall grass.

A sign against the weather-battered chain link said, “No entry. Trespassers will be prosecuted.” The sign’s fluorescent laminate looked about as old as the first Harry Potter film, no doubt fixed there to ward off early fans. After waiting for a distant car to round the bend out of sight, I heaved my backpack, then my body, over the fence and into the low brush on the other side.

My arms, face, and neck smarted from more than a couple of scratches from the knotty branches between the access road and the tracks. No matter: my train left in 70 minutes, and I was determined to see the valley from the viaduct, local laws be damned. My boots slid among the loose, irregular gravel once I touched onto the side of the rail line. The way was surprisingly narrow.

Reaching out to the corner of the viaduct wall, I realized that what I touched was probably built for visitors like me, included by forebearing engineers protecting delinquent climbers from their own stubbornness. Listing against the wall, thighs and lungs beleaguered, I felt the extra satisfaction of a task accomplished despite warnings never to have taken it on. The sensation was not unlike the one described by a Russian man interviewed last month after he successfully climbed one of Egypt’s great pyramids. “Chilling delight, absolute happiness,” he said of the experience.

From the viaduct, I took a picture of the monument to the Catholic rebel at the water’s edge. Some constraints are made to be broken.

2.

One summer, in Istanbul, I fell in with a clutch of dental students who put me up in the apartment they shared not far from the Serkeci Terminal train station. I had been couchsurfing. They saw my need — I had arrived alone, and broke — and so committed to spending the next three days showing me around. At the Topkapi Palace, the traditional residence of Ottoman sultans, they refused to let me pay. I did the conversion later and it was something like 16 dollars American, no short sum for a student budget.

The Blue Mosque offered prayer time for them and a neck-straining hour of gawking for me. The Hagia Sophia left me confused. A mosaic Jesus loomed over the entrance. Black-and-gold Arabic calligraphy reading Allah Akbar covered twin giant discs, each more than ten feet across, hanging from the ceiling.

At the touristy Camberlitas Hammam, a sweaty man in a towel and plastic clogs who looked like he might have once played tight end for the Philadelphia Eagles excoriated my scalp and back. “Did you enjoy your first hammam?” the guys asked me afterward. The touch of the tee-shirt on my skin brought me to the verge of whimpers. I said nothing and looked forward to whatever plans they had next, because anything would improve on the supposedly therapeutic flogging I’d just survived.

Down one of the rabbit-hole tunnels that make the city’s Grand Bazaar a (barely) navigable labyrinth, we issued out into the partially open-air patio of a hookah café with bustling waiters. Smoke of multiple scents billowing from tables. An inexplicable giant aquarium dead center, goldfish swimming lazy loops inside.

Crowding around a café table meant for two, my circumstantial friends talked excitedly about what to get, jabbing fingers into the plastic menu. In rough but very earnest English they asked me, “Do you like apple flavor?” and “Would you fancy mint?” I paused before choosing the first. They shouted to the nearest waiter for a hookah pipe.

When it came, the waiter turned over the embers with tongs, using the expert, measured gestures of a professional grown blasé from the task. I had never smoked anything in my life, but the presentation had me salivating. A handful of plastic mouthpieces, looking like golf tees wrapped in see-through candy wrappers, were passed around the table. I picked a bright red one, fitted it into the notch at the end of the hose, and inhaled.

Smoke rolled an apple-flavored coating down my throat. The stress of the hammam melted as I sank into my seat cushion, no chemicals at work save for the flavored smoke. I breathed a protracted breath into the streaky sunlight, thanking the heavens I had come to Istanbul and found these guys, then sat up when I realized I hadn’t passed the hose.

“No thank you,” my neighbor said. The others conveyed the same polite, smiling refusal. “We are Muslims.”

3.

I visited Paris last December at the tail end of a business trip. I had lived there during graduate school and looked forward to revisiting my old haunts. For a year I lived in a seventh-story shoebox in the 6th arrondissement, in St.-Germain-des-Prés, a neighborhood known for its intellectual gravitas, the Café de Flore, and the out-of-control apartment prices that now edge out all but the global one percent who fancy having a real-life Parisian pied-à-terre.

Ms. Carla Esposito, an Italian whose circumstances as a prosperous and happy widow I never dared press her about, was my landlord and cut from that very mold of cosmopolitan wealth. Her place looked over what is arguably the most glorious of all Haussmannian boulevards in the city, the rue de Rennes. Now I was strolling that avenue again, hunched from the cold but cheered by the memories of a thousand trips along the street, to school, the grocery store, and the movie theaters famously associated with the Montparnasse district down the avenue. The morning sun seemed to take its sweet time warming the pavement and the canyon-like channel of buildings and road.

When I saw a young family exiting the carriage-sized gate of my old building, I shuffled furtively behind them and grabbed the door before it could latch. I slipped in before anyone noticed. The entrance’s darkness reminded me of coming home late from cafés and parties with my school friends. I moved quickly, assuring silent steps along the red-clay ground, past the row of garbage bins, and up the narrow staircase to the tiny apartments above, which Ms. Esposito owned, too.

The second-to-last story flattened out into a winding hallway, tight enough to trigger a panic attack in the mildest of claustrophobics. I knew the way by heart, its left-right, right-left tattooed in my mind. Huffing up the final flight, past a rotted wooden ladder, I recognized the rain-gray paint, then the chewed-up wooden flooring of the top story. Some new tenant was playing a radio in their room, number 33. All those years ago, I had rented number 32, and felt a surprising tinge of jealousy when I realized that someone else was probably now renting my old pad. Sure, it was cramped and dingy, but it had been mine all the same.

Nostalgia overtook me. I imagined myself again standing in that space. It felt just as visceral that moment as when I lived in it, hung up my wet clothes, and cooked meals on its hotplates. Winter nights I would wear a sweater to bed, beholden as I was to the weather just outside the window.

I saw another window that day, just before I left the building. The door to the bathroom at the end of the hall hung open. I hurried in and locked the door behind me, then stepped a foot up onto each side of the toilet. It sat loose in its fitting, and a small gap ran between chunks of mortar and the toilet’s base.

Out a square-foot hole to the sky, Paris’s rooftops spread before me, squatty clay chimney tops and century-old shingles forming waves of architecture just as random as if in the ocean.

A bird flew by, then another. The Saint Sulpice cathedral, just around the corner, offered spires no longer shrouded in the scaffolding that had covered them when I lived in Paris. Better than before, they shone in the afternoon light, an exquisite winter sun illuminating their sandstone facades. 

Hopefully, I prayed, walking out into the anonymity of the street, I had changed for the better, too.

Will Fleeson is a press officer at the French Embassy in Washington, DC.