Pyramid

A pyramid was a three-dimensional structure composed of four or five sides composed of (usually) triangular shapes.

The great pyramids of Egypt of Earth were built as grand tombs for the pharaohs. They dated back to the times of the Old Kingdom and Middle Kingdom. (PROSE: A History of Humankind) These pyramids, such as the Great Pyramid of Giza, (TV: The Daleks' Master Plan et al.) were well known to other races.

One splinter of Scaroth claimed to have caused the pyramids to be built, (TV: City of Death) though the Doctor was sceptical of this claim. (PROSE: A History of Humankind) The Osirans also influenced the building of the pyramids, and other pyramids were definitely constructed by 'aliens'. (TV: Pyramids of Mars, PROSE: Dead Romance) Osiran war missiles were pyramid-shaped and used "pyramid power". (TV: Pyramids of Mars)

Khepren supervised the construction of a pyramid. (TV: The Daleks' Master Plan)

The Exxilons influenced not only the Egyptian, but also the Aztec pyramids during their visits to Earth. (PROSE: The Left-Handed Hummingbird)

Anubian spacecraft had a pyramid shape. (TV: Curse of Anubis)

In a timeline where all of history was happening at once, Area 52 was housed inside a pyramid. (TV: The Wedding of River Song)

The Rings of Akhaten also had a pyramid, a holy site for the Sun-singers of Akhet, seven planets orbiting the same star, all of them sharing the belief that life in the universe originated on that pyramid. In it was a mummy. (TV: The Rings of Akhaten)

The Monks came to Earth in a pyramid from where they could manipulate their simulated worlds. (TV: The Pyramid at the End of the World)

On Vortis, the First Doctor and Ian Chesterton discovered a large stone pyramid. (TV: The Web Planet)