Going on a trip, oldest doesn't want to go

My wife and I have been planning a family trip to Europe for a while now and we're finally able to go. We've given the kids plenty of notice and while the two youngest want to go, the oldest (13) doesn't. He's been dead set on this ever since we told them in December. When we ask him why he doesn't want to go, he just says he doesn't want to with no further explanation. I feel like it would be for the greater good if he went just to experience the different cultures.Our flight leaves tomorrow and we have to decide beforehand. We have grandparents who are willing to and I think actually want to take care of him while we are gone. I trust them completely; it's just I want him to be with us while we are having fun.So what should I do? Do I force him to come with us, or let him stay and enjoy school vacation week with his grandparents? My only worry is that he comes and is absolutely miserable 3000 miles from home and doesn't see the sights to see. via /r/Parenting https://ift.tt/2H3GaSX