As someone who's been to Las Ramblas, I can definitely say it is
worth the visit. I think that all of these list items are worthwhile
less for the actual sight and more for the experience. You don't see
Las Ramblas, you experience it. Same goes for the Eiffel Tower. It's
not so much the tower that's interesting, it's the atmosphere around
it.

 The most beautiful sights to see are truly the
natural wonders of the world. But these are places to say "I've been
there" when you see them in films and pictures.