London: a settlement founded by the Romans, occupied by the Saxons, conquered by the Danes, and ruled by the Normans. This transformative place became a medieval maze of alleys and courtyards, later to be checkered with grand estates of Georgian splendor. It swelled with industry and became the center of the largest empire in history. And having risen from the rubble of the Blitz, it is now one of the greatest cities in the world. From the prehistoric...