A new theory is stirring debate about what may lie hidden beneath one of the world’s most famous ancient landscapes.

For more than 4,500 years, Egypt’s Great Pyramid of Giza has intrigued explorers, historians, and archaeologists, holding mysteries that have long eluded discovery. Now, a tiny, purpose-built robot ...

The researchers who claimed to have found a vast underground city beneath Egypt’s Great Pyramids doubled down on the wild theory Tuesday by saying they’ve found a second “hidden city.” Italian and ...