In April, to mark the day on which Americans are expected to file their taxes, the New York mayor, Zohran Mamdani, filmed himself on Billionaires’ Row, an enclave of super-tall apartment buildings just south of Central Park. When he took office, he said, he would tax the rich, and now, outside the hedge fund billionaire Ken Griffin’s $238m penthouse, he was ready to make good on his pledge. “Today, we’re taxing the rich,” he said with a flamboyant smile, zooming his face into the camera. It was the opening to a short film unashamedly titled Happy Tax Day, New York.

He went into battle armed with stats. According to Mark Levine, NYC’s comptroller (a senior financial executive), the pied-à-terre tax on second homes will raise about $500m annually fromabout 11,200 properties.

Anna Minton is reader in architecture at the University of East London. Her new book, Superprime: The Sterilisation of the City, will be published by Penguin next year