Having made a promise to go on an international adventure every year, Mark knew he wanted to propose in a place tied to one of those adventures. Mark and Joel's first international adventure landed them atop the highest sand dune in Europe, just outside Bordeaux, France. At Great Sand Dunes National Park in Colorado, the highest sand dune in North America stands in great contrast to the surrounding forested mountains. Mark knew that the this was the perfect spot to propose. As he got down on one knee, he reminded Joel of all of those adventures they'd been on and vowed to go on even more. "I would love for you to go on the ultimate adventure with me and be my husband. Will you marry me?" Joel was taken aback, but gave a resounding yes as he joined Mark on the warm sands of the dunes.