From Wikipedia

Pyramids Investigated

The Egyptian pyramids are ancient pyramid-shaped masonry structures located in Egypt.

There are 138 pyramids discovered in Egypt as of 2008.Most were built as tombs for the country's Pharaohs and their consorts during the Old and Middle Kingdom periods.

The earliest known Egyptian pyramid is the Pyramid of Djoser which was built during the third dynasty. This pyramid and its surrounding complex were designed by the architect Imhotep, and are generally considered to be the world's oldest monumental structures constructed of dressed masonry.

The best known Egyptian pyramids are those found at Giza, on the outskirts of Cairo. Several of the Giza pyramids are counted among the largest structures ever built.

The Pyramid of Khufu at Giza is the largest Egyptian pyramid. It is the only one of the Seven Wonders of the Ancient World still in existence.

A view of the pyramids at Giza from the plateau to the south of the complex. From right to left are the Great Pyramid of Khufu, the Pyramid of Khafre and the Pyramid of Menkaure. The three smaller pyramids in the foreground are subsidiary structures associated with Menkaure's pyramid.