Popular culture is often treated as the noisy younger sibling of the fine arts, yet from the penny press to the meme it has been where most people first fall in love with stories, images and songs. Ask someone to define pop culture and you will usually get a list rather than a definition.

Cultural diversity is one of those phrases we hear so often that we rarely stop to ask what it means. The answer turns out to be older, stranger and far more hopeful than the slogans suggest.

Cities, writing, temples and the freedom to make art: a plain-language tour of the idea of civilization, and of the great cultures, from Uruk to Timbuktu, that carried it forward. The word civilization gets used so freely that it can be hard to remember it means something specific.

Ask most people what sport is and they will point to a scoreboard. A winner, a loser, a final whistle.

The idea that painting, music, poetry, sculpture and dance belong together in a single category called art is younger than the piano. Knowing that changes how you read all of them.