Chichén Itzá, Mexico — At the spring and fall equinoxes, the setting sun casts serpent-like shadows along the northern stairs of El Castillo, or “the castle.” Built more than a thousand years ago by ...

For 5,000 years scholars, generals, and mystics have been fascinated by the Egyptian pyramids. That obsession persists in the modern age. Today the Pyramids of Giza are surrounded by desert. But 4,600 ...