Learn how gradient descent really works by building it step by step in Python. No libraries, no shortcuts—just pure math and code made simple.

One of Cairo's must-see attractions is the Great Sphinx, the world's oldest monumental sculpture. Situated by the Pyramids of Giza, the Great Sphinx impresses with its size – it measures 66 feet high ...

This story appears in the January/February 2017 issue of National Geographic History magazine. Amelia Blanford Edwards was one of a stream of European travelers drawn to see the wonders of Egypt at ...