Before our plane landed in Ireland, Alec and I were just like any brother and sister, familiar, but a little complacent about our relationship. After all, how many siblings really know each other after they’ve moved out and started their own lives?

For years, we’d lived under the same roof sporadically, over holiday breaks and during odd months of the summer. Alec was three years younger than me, my childhood best friend who finished growing up long after I went away to college. But in Ireland, we were both students taking the summer off, interning at the same company, sharing the same apartment, and driving the same car.

The moment we disembarked from that plane, we became co-workers and roommates. We didn’t have much of a choice about that. But we did choose to add another important title: travel buddies.

From Monday to Friday, 9 a.m. to 5 p.m., we worked in an office, where we spent our lunch breaks befriending co-workers and quizzing them about their weekend excursions. Then, late Friday night or early Saturday morning, Alec and I piled into our car, and he drove us to the cities and sights recommended by the lads in the office.

Side by side, we learned that the Emerald Isle is both greener and grayer than our home state of Utah. The Irish landscape zipped past in fields that looked as if they’d been doused with green paint, dizzying country roads that bisected small villages, unending fleecy clouds that hovered near the horizon. Alec and I bickered occasionally, especially when bad directions led us astray, but usually, we just enjoyed the drive and took turns choosing the music.

Naturally, some weekend trips were better than others, but an early-summer visit to Inisheer ranks among both of our favorites. Inisheer is part of the Aran Islands, a series of limestone dots and dashes just off the Irish coast, so we had to board a ferry to make our way there.

When we spilled off the boat and onto the tiny island, we rented bikes from a woman who laughed when I asked for padlocks. She sent us off without further ado, and we made the steep ascent up a nearby road. The climb was easy for Alec, who had been on a high school mountain biking team; I slowly made my way to the top of the hill with my breathing (mostly) in check.

Low stone walls lined both sides of the road, zigzagging across the island and dividing the land into green paddocks. Ahead of me, Alec rode on, intent on reaching the rusty-red shipwreck our co-worker had described. It had lain exposed on the island’s eastern tip for more than 50 years, and he couldn’t wait to see it.

We reached the shipwreck quickly, before any fellow passengers from our ferry ride overtook it, then circled on foot. It was massive, broken, and crumbling, with loose parts strewn across the surrounding boulders. Carefully, we spiraled in until we stood at the ship’s gaping mouth, poking our heads inside to examine the wreckage.

Only a hollow shell remained, and I could see the ocean through an empty window on the opposite side. The sea was calm and glassy, but the ship’s metal was as rough and distorted as tree bark. My older-sister instincts kicked in as Alec prowled inside, but I was too interested to ask him to come back. I slinked in, warning him not to touch anything, and took a look around.

Alec lives for moments like that, when he can roam abandoned buildings and creep around construction sites. He usually sets forth with his friends or our younger brother, worried that I might balk halfway through an adventure.

Not that day on Inisheer.

We clambered out of the ship a few minutes later, happy with our self-guided exploration, and took photos near the water. The first big wave of tourists hit the wreck just as we consulted our paper map and remounted our bikes.

All day long, we biked across the island, stopping next at a lighthouse, then a ruined castle, an old church, and a rocky beach. The colors blurred as the sun got lower, and Inisheer became a hazy blend of blue and gray.

A couple of weeks later, we rode bikes again, this time through Killarney National Park, where we stopped often to gaze at the landscape and explore the ruined stone buildings. My national parks enthusiast of a brother felt right at home, even on the other side of the Atlantic.

Later that summer, we trekked along the Causeway Coastal Trail in Northern Ireland, edging along the cliffside path and ending our hike at Giant’s Causeway. I enjoyed listening to the crashing sound of the water, wending my way through the rock pillars; Alec loved capturing the moment on his camera.

All summer long, we wore out our feet in cities and towns: Dublin, Galway, Limerick, Doolin, Ennis. I directed us toward castles, museums, and archaeological sites; Alec was a good sport, even when our interests diverged.

It was the summer that I got to know my brother as an adult. He loves being outside and taking nature photos. He works hard but doesn’t take himself too seriously. He’s a better golfer and a faster go-karter than I am. He gets snappy when he’s hungry, and he loves music that I usually can’t stand.

I’m not quite sure what he learned about me. You’d have to ask him.

We’ve been back in the U.S. for a while now, both settled back into our ordinary lives. But we’re closer confidants and better friends now than we were before we moved to Ireland for that summer.

For both of us, it was a summer of growth. And for me, it was a reminder that travel brings us closer to people — even the ones we’ve known as long as we can remember.