Increased urbanisation across Europe has meant that a larger proportion of the population is now living in urban cities.
The health effects of more people living in cities are already being noticed by researchers: it is estimated that nine million people die every year as a result of air pollution.
In Madrid, El Retiro Park uses silent, solar-powered boats to navigate through the lake in a bid to reduce excess pollution in the park.
While many city parks in Europe are visually stunning, with buildings designed to attract more people, these parks can fall short of being truly eco-friendly in their maintenance.