The answer lies in ancient Greek history.
The "wonders of the world" concept dates back to the fifth century B.C., when the Greek historian Herodotus contemplated the amazing achievements of art and architecture created by the Persians and the Greeks.
However, Antipater of Sidon, who wrote in the second century B.C., is credited with putting together the first list of wonders.
Many historians now believe that the list served as a guidebook for ancient "tourists" traveling to see the revered sites.
The list that we acknowledge today was compiled in the Middle Ages and comprised the seven most impressive man-made monuments from the ancient world.
Since the list came mostly from ancient Greek writings, though, only sites that would have been known to the ancient Greeks were included.
Today only one of the original wonders still exists, and there is doubt that all seven ever existed, but the concept of the wonders of the world has continued to excite and fascinate people everywhere for centuries.
Constructed around the year 2560 B.C., the great Pyramid at Giza is the only wonder that remains standing from the original list of seven.
Egyptologists believe that the stunning monument, constructed from approximately 2 million blocks of stone and believed to have taken approximately 20 years and 20,000 men to complete, was built as a tomb for the fourth century Pharoah Khufu.
Throughout history, experts have marveled at the remarkable accuracy of the pyramid's construction. The base, which covers 13 acres, is almost a perfect square and each corner is aligned almost exactly with the four points on a compass.
Excavations have unearthed three chambers, known as the Unfinished Chamber, the Queen's Chamber and the King's Chamber. In addition, using a robot, researchers have explored many of the tunnels and alleyways that run deep into the monument.
The Hanging Gardens of Babylon were reportedly a centerpiece of the ancient metropolis of Babylon (about 50 miles south of modern day Baghdad).
Strangely, the historical records of the Babylonians do not mention the wondrous hanging gardens, leading some scholars to doubt that they ever existed.
Regardless of the omission, stories of the gardens spread over time throughout the ancient world, and ancient writers recorded numerous descriptions.
The story goes that King Nebudchadnezzar II, who ruled in the seventh century B.C., built the hanging gardens to reproduce the mountain scenery that his wife was accustomed to from her homeland of Medina.
Despite the romantic image of gardens that floated in midair, many experts now agree that if they existed at all, the hanging gardens were an elaborate series of gardens "terraced" one on top of another on a hilly countryside.
Standing more than 40 feet tall and constructed of ivory and gold, the statue of Zeus within the Temple at Olympia (on the west coast of modern Greece) was constructed by the Greek sculptor Pheidias around 435 B.C.