And rumors of a tantalizing crystal pyramid found on ocean's floor go back at least as far as the 1960s, which is when a Dr. Ray Brown claimed he came upon such a structure while scuba diving in ...

This square-based pyramid, like most pyramids, has been thought to have just four triangular faces. However, in a surprising turn, recent studies have shown that the one of the Seven Wonders of ...

It goes without saying: a triangular pyramid is always surrounded by six quadrangular pyramids. But in da Vinci's drawing (again reproduced, directly below) this isn't the case: ...