Built: From about 2700 to 2500 B.C.
Location: Giza, Egypt, on west bank of Nile River near Cairo
History: The Egyptian Pyramids are the oldest and only surviving member of the ancient wonders.
Of the 10 pyramids at Giza, the first three are held in the highest regard. The first, and largest, was erected for the Pharaoh Khufu. Known as the Great Pyramid, it rises about 450 feet (having lost about 30 feet off the top over the years) and covers 13 acres.
It's believed to have taken 100,000 laborers about 20 years to build the mammoth Khufu pyramid, using an estimated 2.3 million blocks. By one theory, crews dragged or pushed limestone blocks up mud-slicked ramps to construct the royal tombs.
Many scholars think the pyramid shape was an important religious statement for the Egyptians, perhaps symbolizing the slanting rays of the sun. Some speculate the sloping sides were intended to help the soul of the king climb to the sky and join the gods.