Giza, Egypt: Great Pyramid of Khufu
Say "the pyramids," and most people picture this famous trio towering dramatically above the desert sand not far outside modern Cairo. The northernmost of the three, built circa 2551 B.C. for Pharoah Khufu, is known simply as the Great Pyramid---and with more than 2 million stone blocks forming a geometric pyramid 450 feet high (originally 481 feet), it certainly is. Although it is no longer the world's largest manmade structure, as it was for over three millennia, it is the largest of all the ancient pyramids. The ancient Greeks deemed it one of the Seven Wonders of the World, and it is the only one of those seven that has survived to the present day.