Many city dwellers do their best not to see the homeless people who share their streets and pavements. Donald Trump once famously insisted that his security guards clear all tramps and panhandlers from the pavement in front of Trump Tower. Even when the homeless aren’t being chased away, they can seem invisible. In 2014, the New York City Rescue Mission, a shelter, conducted a social experiment, Make Them Visible, in which they filmed participants walking past relatives disguised as homeless people. None of the participants noticed their relations sitting on the street. “We don’t look at them. We don’t take a second look,” said Michelle Tolson, director of public relations for the organisation.