A pyramid is named by the shape of its ‘base’. A pyramid with a triangular base is a triangle-based pyramid. A tetrahedron is a triangular pyramid with all equilateral triangle faces.

A diver has described his experience of uncovering underwater ‘pyramids’ after spotting ... The findings have since been called the “real life Atlantis” after being observed off the ...

However, this natural marvel owes its unique shape to erosion rather than human or alien intervention. A Natural Pyramid Among Antarctic Peaks The unnamed mountain, standing about 4,150 feet tall ...