(CNN) — American graduate student Dan Giedeman spent much of his first trip to Paris inside a conference room.
It was September 1998 and Dan, then 27, was studying for a doctorate in economics at Washington University in St. Louis, Missouri. When his professor invited him to attend a meeting in the French capital, Dan jumped at the opportunity.
"I grew up in the middle of the United States, the Midwest. So I'd never had a chance to go to Europe, or really anywhere outside the country," Dan tells CNN Travel today. "I was thrilled to go." On his last day in Paris, Dan woke up late. He'd been out for drinks with other conference attendees the night before. He realized it was less than 24 hours before his flight back to the US and he'd barely seen the city.
"I can't leave Paris without at least seeing the Eiffel Tower," Dan thought. He dragged himself out of his hotel room, dressed in his conference-appropriate tie and shirt, and headed to the 7th arrondissement.
Waiting in line for the elevator to the top of the Eiffel Tower, Dan noticed a woman who met his eyes. The two smiled at one another.
This was Esther Wieland, a 23-year-old preschool teacher visiting from Zurich, Switzerland.
"I was by myself, and I thought a Monday morning would be not as crowded to go on the Eiffel Tower," Esther tells CNN Travel today. "So I went sightseeing by myself and stood in line, and noticed him."
"We were sort of weaving back and forth past each other," recalls Dan.
The two temporarily lost sight of one another when an American family engaged Esther in conversation.
But as the elevator arrived at the top of the tower -- the tourists spilling out to admire the city below -- Dan and Esther spotted one another again.
The two separately wandered around the viewing platform, taking stock of the panoramic views of Paris and occasionally stealing glances at one another.
"I should talk to her," Dan thought.
But would he attempt to speak French? What would he say? What if it was really awkward?
"If I talk to her, and it doesn't go well, I'm by myself. No one in the world ever has to know," he decided.
With that in mind, Dan politely approached Esther, asking, in broken French, if she would take a photo of him with the view.
"I had had a year of college French, so I didn't know what I was saying," recalls Dan.
"I couldn't understand his French," says Esther today. "So I said, 'Can you repeat yourself again?'"
Embarrassed, Dan reverted back to his native language. Esther explained she was fluent in English.
"Dan seemed a little bit awkward when he spoke to me, which put me at ease," recalls Esther. "And I liked his eyes."
After she took the photo, the two started wandering around the viewing platform in tandem.
"We walked around the entire top of the tower looking at the views together," says Dan.
Esther took this photograph of Dan on top of the Eiffel Tower on the day they met in 1998.
Courtesy Dan and Esther Giedeman
For the next half an hour or so, the two walked and talked, admiring the city below. Then Dan asked Esther if she would like to get a coffee at the Eiffel Tower cafe.
Esther suggested they grab something to eat on the ground.
"I suggested lunch instead in part because it was lunch time and also I thought it might give us a little bit more time to talk," Esther recalls.
"We had already indicated that neither of us really had plans for the rest of the day, so this was sort of like an adventure. And it was a beautiful day and I thought we could eat outside somewhere."
"I don't know if it was love at first sight. But there was certainly that possibility of love at first sight," says Dan.
Eight hours together in Paris
Dan took this photo of Esther in the Jardin de Luxembourg after lunch.
Courtesy Dan and Esther Giedeman
Dan and Esther descended the tower together and found a pavement table at a nearby brasserie on the Place de l'Alma.
"We had a nice view of the Eiffel Tower from our table," recalls Dan.
Over a croque monsieur and caprese salad, sipping first sparkling water and later espressos, the two continued the conversation they'd started on the viewing platform.
Esther explained she was in town visiting her aunt and uncle, who lived just outside of Paris. Dan told Esther about his studies back home in St Louis, as well as his four siblings. Esther talked about growing up as an only child, and her period working as an au pair in London.
"I was nervous a little bit," says Dan today. "But the other thing too was I was just enjoying the day."
"I felt comfortable," says Esther. "It just seemed like we knew one another, it didn't seem like it was the first time."
After finishing up lunch, the two headed to the Jardin de Luxembourg together. Dan took a photo of Esther by Luxembourg Palace.
The two also asked a passerby to take a photo of the two of them together. Dan beaming in his blue shirt and tie, Esther smiling in a cream pullover.
Dan and Esther wandered around the Jardin de Luxembourg together after lunch. They asked a passerby to take this photograph of the two of them.
Courtesy Dan and Esther Giedeman
They wandered past the imposing Medici fountain, past sunbathers enjoying the late summer sunshine, past rows of flowers enjoying a final bloom. Then Dan asked Esther if she would like to exchange addresses.
"Well, if I write you, will you write me back?" asked Esther.
"That was the first actual indication, really, that she actually was enjoying the day too, in a way, that she wasn't just having pity on this poor foreigner who was wandering around Europe on his own," says Dan, laughing.
Esther was catching a train back to her aunt's house that evening, so Dan accompanied her to the Gare Saint-Lazare. On the platform, they scribbled their addresses and phone numbers on scrap pieces of paper.
"We thought that might be the last time we saw each other," says Esther.
"I gave her a little kiss on the hand," says Dan.
Dan took another photo of Esther as she stepped onto the carriage.
"We looked at each other as the train pulled away," he recalls.
Afterward, he felt listless.
"It was kind of like a melancholy feeling, because I had such a great day, but we were sure that that was the end of it," he says today.
On his way back to his hotel, Dan called into a store to look at postcards. He selected one with a photo of the Eiffel Tower on the front.
"I expect that for the rest of my life I will think of you whenever I see an image of the Eiffel Tower,'" Dan wrote to Esther, and posted it right away.
Then he called one of his sisters from a payphone, telling her about meeting Esther and the amazing afternoon they'd shared.
Meanwhile, Esther sat on the train, thinking about Dan.
"I just remember being sad, leaving with the train and saying goodbye," she recalls today.
"There was no promise that we would ever see each other again, it was just that idea of, if I write to you, we'll write each other back," says Dan.
Writing postcards
Dan and Esther started writing to one another following their Paris encounter.
Courtesy Dan and Esther Giedeman
Back at her aunt and uncle's house, Esther peered at the map of the US that hung on their wall. She was trying to find St. Louis, the city where Dan lived.
Later that evening, she wrote in her journal about her Eiffel Tower encounter. Esther had written about her crushes in her diary since she was a teenager.
"Whoever I was dreaming about, I always used a code name," says Esther. "And it was always 'Dan.' And it was so funny, I ended up with the real Dan."
A couple days later, Esther posted Dan an Eiffel Tower postcard, not knowing he'd sent a similar postcard to her.
The arrival of these initial cards kickstarted a epistolary correspondence.
"There was often a 10-14 day period between sending a card and receiving a letter in reply. So when a card came, it was like Christmas and a surprise party combined," recalls Dan.
After about two months of letter writing, Dan called Esther for the first time.
"This was before cheap international phone calls," says Dan. "And I just gave her a call -- I thought we'd maybe talk for a couple minutes -- and we talked for about an hour. So it was the most expensive first date I think I've ever really had."
This soon became a routine. Every Sunday, during Dan's afternoon and Esther's evening, the two would connect on the phone. During the week, they'd write letters.
After several months of letters and calls, the two arranged that Dan would visit Esther in Zurich, Switzerland.
His flight was booked for May 1999, around nine months after the Eiffel Tower meeting.
"When I flew over to Zurich to go see her it wasn't clear still whether it was a romantic connection or not," recalls Dan.
They were both excited to see one another again, but neither Dan nor Esther knew what to expect.
"We were friends," says Esther. "We both hoped we had feelings, but we weren't talking about it. We just got to know one another as people and as persons."
"It was like this friendship with maybe the possibility. But I think both of us were a little bit cautious because we're not sure exactly what the other person's thinking," says Dan.
A Swiss reunion
Waiting at Zurich Airport for Dan to arrive, Esther was nervous. But as soon as she saw him, the ease she'd felt that day in September returned.
"It was like we'd picked up where we left off in Paris," says Esther. "I remember wondering, the second time I saw him, 'How is it that I know so much about this person, how they think, who they are?' The chemistry kind of fell into place."
That first day, Esther took Dan to see the cascading Rhine Falls. The second, they went to the medieval city of Lucerne.
Dan had attended the September 1998 Paris conference on the request of one of his professors, Dr. Douglass North.
North had been charmed to hear of Dan and Esther's chance meeting on the Eiffel Tower, and had since taken an interest in their burgeoning connection.
By coincidence, North was going to be in Zurich at the same time as Dan, giving a talk at the university. He suggested to Dan they should all meet up.
So after a day wandering around Lucerne, Dan and Esther drove back to Zurich to meet the professor and his wife at an upmarket restaurant called Kronenhalle.
"It was actually kind of funny that our first actual kind of real date was a double date with this Nobel Laureate and his wife, who were in their 80s," says Dan. "This was my second day there -- we still didn't know if there was a romantic connection or not."
Esther recalls being wracked with nerves.
"I wasn't the greatest of drivers. So that day, I ran into a pillar, damaged the car, got a speeding ticket, then we had to meet this prestigious professor at a restaurant, I was nervous," she says.
"I felt like in 'Pretty Woman,' you know, I didn't know anything -- it was the fanciest restaurant that I have ever been in."
But the Norths were very welcoming and it was a fun evening. After Dan and Esther said goodbye to the professor and his wife, they walked along the banks of Lake Zurich and kissed for the first time.
The two spent the rest of the week sightseeing together -- including a trip to Bern and a day trip to Milan -- and visiting Esther's family across Switzerland.
Puzzle pieces
Back home in the US, Dan told his loved ones about the visit, explaining that he and Esther were going to try and make a long-distance relationship work.
"Of course you had to leave the country to meet somebody, because nobody in America would like you," joked one of Dan's brothers.
He was kidding, but other people in Dan's life were genuinely a little worried. He remembers his mother was a bit apprehensive, and some friends told him it would never last.
But later that summer, Esther flew to the US to visit Dan for three weeks. She immediately gelled with his loved ones, quelling any concerns.
"Once my family got to know her, I think they were hoping too that things might work out between us," says Dan.
As for Esther's family, her mother was initially skeptical when her daughter returned home from Paris starry-eyed -- as a teenager, Esther had often fallen for guys she met on vacation, but the spark had never gone anywhere.
But as time passed, it became clear to Esther's mother that her daughter's relationship with Dan was something deeper.
"She knew that I was more involved, that I was really hoping and struggling and invested a lot," says Esther. "And I think that's when she knew."
“I expect that for the rest of my life I will think of you whenever I see an image of the Eiffel Tower”
From Dan's first postcard to Esther
Over the next couple of years, Esther and Dan sustained their relationship through letters, phone calls and a meet-up in Europe or the US every six months or so.
Their longest phone call during this period spanned eight hours.
"There was a time I remember sending letters every day. I didn't care, just every day. I probably wrote the same thing over and over," recalls Esther.
Saying goodbye at the end of each visit was hard. But they always parted feeling hopeful.
"Each time, I think our relationship had built up even more that we knew that it was going to continue," says Dan.
"We just took it step by step," says Esther. "We both hoped from the first day I think, deep down, that it might work out, but it was like a puzzle -- every time we had a piece, it fit."
Next steps
Dan and Esther got engaged on a trip to Venice.
Courtesy Dan and Esther Giedeman
Three years passed this way. By the early 2000s, Dan was finishing up his doctorate. He was hoping to secure a role as a professor and was unsure where he might end up.
As he and Esther mapped out their next steps, this unknown seemed to present an opportunity.
"There would be a possibility for us to both move someplace new together," recalls Dan. "It wasn't like one person was going to make a choice -- 'I have to leave everything I know to go over there' or 'You're going to leave everything you know to go here.'"
A job offer came through at Grand Valley State University in Grand Rapids, Michigan. Not long afterward, Dan proposed to Esther on a trip to Venice, Italy.
Their wedding took place in a small church in the town of Buch am Irchel, overlooking the Rhine Valley. A reception followed in a Swiss winery.
"We had food and drinks and Esther's friends arranged different games and activities for us to do," says Dan.
Esther took Dan's name, becoming Esther Giedeman.
Their wedding was attended by American and Swiss friends and family members. One of Dan's brothers, who served as his best-man, joked that the couple had met in Paris, got engaged in Venice, got married in Zurich -- and now they were moving to Michigan.
"Grand Rapids isn't quite the same as Paris or Venice," admits Dan.
But after years of letter-writing and transatlantic phone calls, Dan and Esther were thrilled to finally be in the same place. Grand Rapids became their home, and the two still live there today, now with three children.
Dan is still an economics professor, while Esther works as an artist.
Return to Paris
Dan and Esther on the top of the Eiffel Tower on their return visit.
Courtesy Dan and Esther Giedeman
Throughout their 20 year marriage, Dan and Esther have made regular visits to Switzerland. They even lived in Germany for a while, when Dan was on sabbatical from his university. Their kids have grown up connected to their American and Swiss heritage.
But despite frequent visits to Europe, Dan and Esther didn't make it back to Paris together until 2016.
This return to the French capital may have been a long time coming, but it was all the more poignant for it.
Dan and Esther in the Jardin du Luxembourg, almost two decades later.
Courtesy Dan and Esther Giedeman
"We went for a week and stayed in an Airbnb in the middle of the city with our three boys and that was really fun," says Esther.
The couple returned to the top of the Eiffel Tower and walked around the Jardin du Luxembourg, this time with their sons in tow, the family posing for photos in the same spots Esther and Dan had last visited in the late 1990s.
As they wandered around Paris, Esther and Dan found themselves reflecting on the serendipity of their first encounter.
The couple posed for a photo at the top of the Eiffel Tower with their three sons.
Courtesy Dan and Esther Giedeman
Dan says his old professor, Douglass North, who has since passed away, used to refer to himself as Dan and Esther's "fairy godfather."
If it wasn't for him recommending Dan for the conference, Dan wouldn't have been in Paris in the first place. But that was just one of several fortuitous decisions that lead Dan and Esther to be wandering the top of the Eiffel Tower at the same time.
"If we had just been five minutes apart, we would not have been in that line going back and forth, and just exchanging those glances at each other," says Dan.
Dan and Esther kept all the letters they wrote to one another.
Courtesy Dan and Esther Giedeman
Neither Dan nor Esther woke up that September morning expecting to meet a life partner.
"An economics conference is not something you go to looking for romance," says Dan.
But the happy coincidence of their encounter made them consider the importance of being open to unexpected possibilities in life.
On Dan and Esther's wedding invitations was printed a mantra that sums up this outlook: "Give every day the chance to be the best of your life."
They still have all the letters they wrote one another, including those first postcards from Paris, all stored in a hat box emblazoned with the Eiffel Tower.
"I expect that for the rest of my life I will think of you whenever I see an image of the Eiffel Tower,'" Dan wrote to Esther on that first postcard.
"That certainly turned out to be true," he says today.