As I get older, there seem to be more and more stairs to struggle up and down,” sighs Barbara Rushton, 78, of north London. “I try to regard them as an exercise challenge, but they make getting about increasingly exhausting. Rushton is far from alone in finding that the urban environment has become more inhospitable as she has aged. Time and again, studies with older citizens reveal similar kinds of frustrations. Sometimes these are problems with obvious solutions - there not being enough benches, for instance, or uneven paving. Other times, they are more profound issues, such as a sense of isolation caused (in part) by the way that towns and cities are laid out. According to charity HelpAge International, there are more than 500 million people aged 65 or over living in cities worldwide. In many ways, this is a huge success story - testament to improved public health and lifestyles. However, it is also an enormous demographic challenge - the World Health Organization reckons the 60+ demographic will double globally by 2050. Yet, at present, most cities continue to be designed for the needs of the young and working people. With urban populations all over the world inevitably getting older in the coming decades, how should cities prepare?