If you are doing something for a magazine-type assignment, you could write a “travel article” about one of the highest places in the world. You could say that the tourists there felt like they were on top of the world. Or, you could write a story about a major sporting event or competition that a team had won, and “they all felt as if they ere standing on top of the world” (aka, they were really happy). With these kinds of things you just have to sit and think about a situation that those words would fit in. It’s all up to the imagination. :)
