Peering through a hotel window on the drizzly morning of Aug. 7, Carol Clarke finally spotted the van. When it pulled up and a jet-lagged woman stepped onto the curb of the busy London street, Clarke dashed outside. "That's her," she cried. As the two embraced, Clarke tearfully whispered, "It's you."

The women had never met, yet they knew one another well. Their relationship began 37 years ago, when Caren Gottesman, then a 10-year-old Girl Scout from Jericho, N.Y., was assigned an overseas pen pal named Carol from Essex, outside London. At the time Gottesman had one thought in mind: "I wanted my Girl Scout badge." But what began as a means to an end gradually became a labor of love. "My first letter told her the basics: my name, problems I had in certain subjects," recalls Gottesman, now 47 and a mother of two living in Cooper City, Fla., with her CPA husband, Allan, also 47. "She wrote back and told me the same kinds of things."

Over the years their twice-monthly correspondence deepened as they shared the joys and heartbreaks of school and boyfriends, then husbands, careers and family. "Because Caren is so far away, I knew she would never tell anyone else," says Clarke, 47, a receptionist who raised four children after her 1980 divorce. "So I told her lots." They also exchanged photos and occasionally spoke by phone. Then this spring, as Gottesman planned her 25th wedding anniversary, she had a brainstorm: "To go to London to meet Carol."

At Clarke's house in Essex, the pen pals swapped stories and gifts: from Gottesman, a laptop and a gold charm bracelet with a heart inscribed "37 years of memories"; from Clarke, a fruit-and-flower basket and a gold earring and necklace set. "We grew up together, going through the wonderful times and the bad," says Clarke. "After all those years, we couldn't help but be close."