The original 7 Wonders of the World were sites that ancient Greeks determined to be amazing feats of engineering and beauty. Of course they could only consider those things that were known to them, so all of the sites are located in the areas surrounding ancient Greece. Of the original wonders, only the pyramids of Giza exist today.
Two thousand years later, someone decided to update the list. Over 200 sites from all around the world were nominated for the honor of being one of the 7 Modern Wonders, and 100 million people voted on their favorites. Several countries complained about the methods and results of this global popularity contest once the winners were announced. I don't agree that all of these are really WONDERS; I think there were better contenders that didn't make the cut. But of course everyone has an opinion.
Sour grapes aside, the new Wonders are:
The Great Wall (China)
The ancient rock city Petra (Jordan)
Statue of Christ the Redeemer (Brazil)
The hilltop city of Machu Picchu (Peru)
Chichen Itza pyramid (Mexico)
The Colosseum in Rome (Italy)
The Taj Mahal (India)
To me, "Wonder of the World" means it's hard to imagine how the thing came to be. It defies logic as to how people were able to create it using the tools and technology of their era. It makes us wonder who built it and for what purpose. At the very least, even if we know how the thing was built, it was extremely difficult to accomplish and is the only one of its kind.