Charles Piazzi Smyth was a British astronomer who was Astronomer Royal for Scotland from 1846 to 1888; he is known for many innovations in astronomy and, along with his wife Jessica Duncan Piazzi Smyth, his pyramidological and metrological studies of the Great Pyramid of Giza.

The Great Pyramid of Giza is the largest Egyptian pyramid. It served as the tomb of pharaoh Khufu, who ruled during the Fourth Dynasty of the Old Kingdom. Built c. 2600 BC, over a period of about 27 years, the pyramid is the oldest of the Seven Wonders of the Ancient World, and the only wonder that has remained largely intact. It is the most famous monument of the Giza pyramid complex, which is part of the UNESCO World Heritage Site "Memphis and its Necropolis". It is situated at the northeastern end of the line of the three main pyramids at Giza.