As we mark 15 years since Occupy Wall Street, it is worth remembering that the movement against inequality has a long lineage. The Gen Z-led protests flooding the streets of India, Kenya, Bolivia, and Tunisia today have been building for generations.

On the last day of November 1999, tens of thousands of people shut down the World Trade Organization summit in Seattle. Trade unionists marched alongside environmentalists, students locked arms with farmers, and for a few extraordinary days the people who run the global economy could not get into their own meeting.

The press called protesters a rabble with no coherent demand. They were wrong. The demand was simple and it has not changed: an economy that works for the many, not for a handful at the top.

That demand lands differently when you cannot afford the basics of life. In Seattle, the debate centred on trade rules. Today, people are doing the maths as they stand in front of a grocery food shop not knowing what they can afford to buy, tackle rents that consume the entire salary, and face energy bills that arrive like a threat. What was once an abstraction has become a household emergency.

Seattle did not come from nowhere. Five years earlier, the Zapatistas had risen in Southern Mexico on the day a free trade deal took effect, declaring that ordinary people had a right to refuse the terms being set for them from above.

The Jubilee movement had brought millions of people onto the streets and into churches to demand the cancellation of crushing debts owed by the world's poorest countries.

By 2001 a hundred thousand people were meeting in Porto Alegre in Brazil under the banner "another world is possible," and that same year a young man named Carlo Giuliani was shot dead protesting the G8 in Genoa, Italy.

The powerful learned early that this movement would not simply ask politely. It would demand systemic change.

Then came the crash. In 2008, the same financial system that had been sold to us as untouchable collapsed, and ordinary people were handed the bill while the bankers who broke it kept their bonuses. Out of that betrayal came the next great wave of action.

2011 brought Tahrir Square, the Spanish Indignados, the Greek fight against austerity, the Chilean students, and, in September, a small camp in the shadow of Wall Street.

The Occupy Wall Street movement gave the whole movement its slogan—"We are the 99%." A single phrase that did what a thousand policy papers could not. The protesters drew the line. There is them, and there is the rest of us, and the rest of us are almost everyone.