See The Seven Wonders Of The World
GREAT WONDERS OF WORLD
The ancient Greeks were the first to list the world's seven wonders. The original seven wonders list was compiled for travelers of that time and featured man-made objects of particular architectural or sculptural note.
You might wonder, why seven?
For the ancient world, the number signified perfection or completion. The sum of four and three, even and odd, female and male, it symbolized cosmic wholeness. Although the lists of wonders changed significantly over time, the selections always totaled seven."
The Wonders of the World also includes information on the seven medieval, natural, underwater, and modern wonders