Strange Pyramids Of Egypt And Their Secrets - A pyramid is a building where the outer surfaces are triangular and converge at a point. The base of a pyramid can be trilateral, quadrilateral, or any polygon shape, meaning that a pyramid has at least three outer surfaces (at least four faces including the base). For thousands of years, the largest structures on earth were pyramids. There are so many secrets behind the pyramid. The great Pyramid of Khufu is the biggest pyramid in all.