The first reference to the Seven Wonders of the Ancient World, as an itinerary concept, is found in the works of the historian Herodotus, which place the idea in the 5th century B.C. But it wasn't until some three centuries later that a Greek engineer known as Philon of Byzantium formally compiled the list, in what was essentially a Fodor's guide for the well-heeled Athenian traveler.
The wonders were described as a celebration of "religion, mythology, art, power and sciences'' — humans changing the landscape by building massive but beautiful (note: few would describe the CN Tower as a beauty) structures that would stand the test of time.
Gone are the Hanging Gardens of Babylon built by Nebuchadnezzar II along the banks of the Euphrates; the Statue of Zeus at Olympia; the Temple of Artemis at Ephesus; the Mausoleum at Halicarnassus, the Colossus of Rhodes and the Lighthouse of Alexandria on the island of Pharos. All were built between 2500 BC and 200 BC.
Notice that the Greek list contained the wonders of their empire, or at least what they knew of the world. Philon didn't know from the Great Wall of China.
I'm sure most Classicists will balk at the idea of Herodotus coming up with the idea of Seven Wonders ... there was a good piece in Archaeology Magazine a few years back on the subject; the abstract is online and useful in this regard ...