We leave: It’s inevitable. We sometimes come home: That’s our choice. In the process, we can bring our home country to another land, or we can cart that other, distant country back toward our own and sometimes make it new. And so, every building we have walked through begins to walk through other buildings. Every city skyline we see is informed by the skylines we have glimpsed before. All that we have met meets all that we will meet.

We are connected and remade by what we have seen. I grew up in suburban Dublin, Ireland. I can still hear the ticking of the white radiators. The back door slammed when the front door opened. A house of open windows, I was always flying out of them.

I first left home when I was 17. I went to Mayo, less than 150 miles away. The newspaper building where I worked was down a cobbled laneway. I loved the creak of the stairs, and the rattle of the printing presses below. I took the train back to Dublin only once that whole summer. It seemed to me like an enormous journey, and I recall how thrillingly new my doorstep felt when I returned: It was like brand new territory.

Not long afterward, I broke the border of home again, and went to New York. My heart thumped in my cheap white shirt. I got a job as a cub reporter in the Time Life building and, fired up on innocence and a brash enthusiasm, I ran down Avenue of the Americas, then stopped and lay flat on the ground—for an instant, passersby had to step over me. It was the only way for me to glimpse the panorama. The skyscrapers dizzied me. It seemed impossible that there could only be a small scrape of blue sky. Later that same evening I brushed the dirt off my trousers, ran to catch the D train, got out at Brighton Beach, and rented a tiny room in a clapboard house that smelled of roach spray and sea breeze. I flopped down on the dingy mattress. How, I wondered, could two such diverse settings exist in one city in a single day?

It seemed to me, even then, that sometimes we have to go far away to explore the dynamic possibilities of our own naivety.

A few years later I took a bicycle across the United States. I rode the little blue highways and the back roads. The stars were my ceiling. Camping out, in forests and by riverbeds, I spent 18 months learning the roof of the world. From there it was on toward Japan. The sun caught the top of a Kyoto shrine. My wife and I rented a six-tatami-mat room. Later we found an apartment in the shadow of a Kyushu mountain. Then it was back to New York once more: countless windows outside our window.

There have been so many places since. The clean steeples of Singapore. A villa in Capri. A wooden hut in Slovakia. A church in Saint Petersburg. The tall pillars of the Brooklyn Bridge, strung with wires like a harpsichord. Some of these places have been the sites of fleeting visits, others are regular haunts. My memory is decorated by a series of mirrors that throw color and sound onto yet other mirrors: These places flash across my mind and collide into each other, touch at odd angles, then mingle and disperse.

It strikes me now that the purpose of remembering— and perhaps even the final purpose of travel—is to depict, and therefore render forever present, that which is absent. We return by leaving. Travel is a process of deep renewal. Every time I go away, I am back on my New York doorstep. Every time I am on my New York doorstep, I am stepping away into all those other places I have gone and will go.

I am a citizen of my own imagined elsewhere.

It is difficult to find a grand public adventure these days. This is both good and bad news. Newspaper editors aren’t really captivated by an 80-day journey around the world. Scaling the world’s highest mountains is easy enough if you’ve got the money for it. It’s hard to find a place where a foot hasn’t already been placed, a field that hasn’t been trampled. The Earth is mapped and documented as never before. On the other hand, adventure has become an acutely democratic notion. A lot of us are lucky that the world has shrunk; we can go places our forefathers couldn’t even have dreamed about. But the primary adventure occurs now in our imaginations.