At the Parque del Retiro in Madrid I have witnessed a very interesting example of an age-friendly and health-friendly public space: pedals have been annexed to public benches as to allow old (and young!) people to do exercise while talking to each other!
Public parks are an important public health resource in cities, connecting citizens to nature, providing access to physical activity opportunities, and making sure that social connections happen among citizens.
The WHO Global Network for Age-friendly Cities and Communities states that a key strategy to facilitate the inclusion of senior citizens is to make our world more age-friendly. Cities are a good place to start.