There is no such thing as a Modern Wonder of the World

The classical 7 wonders were geographically limited to the greco-roman world, and we should, of course, complete them with other ancient marvels like Tiahuanaco, Macchu Picchu, Taj Mahal or Stonehenge. No modern or contemporary buildings should make the list though.
The reason is quite simple: what we build today isn’t meant to last, and it won’t. 100 or 200 years from now, I’ll bet that none of them will remain, while the Pyramids of Giza will still be around.