What makes a city green? Factors such as recycling, renewable energy, transportation options, building construction, air quality and emissions make green cities great. Here are some cities that are doing their part to lead us on the global path to a greener future.

Working towards the goal of being the first carbon­ neutral capital before 2025, Copenhagen has made a lot of necessary changes. Lots of electric and manual bikes organic food, clean water, sustainable buildings and hotels, lots of green space and fewer cars are just a few of the ways that help Copenhagen stand at the top of the green cities list.

As the UK's 8th biggest city, and with a steadily growing economy, Bristol is set on making its mark, not only in the UK, but in Europe as well. The next five years will see a huge focus on transportation and renewable energy in the city, as well as a goal of doubling the number of cyclists in that time as well. Bristol is becoming a hub for jobs in low carbon sectors.

Vancouver is pleasant for so many reasons- it's mild and it leads the way for forward thinking and environmental awareness in North America. Residents are very fond of walking and cycling, and government laws have been designed with greenness in mind. It's often considered to be one of the most livable cities in the world, and that isn't enough, it's working towards being powered entirely by renewable energy by the year 2050.