A surprisingly large number involve cars.
In honor of the opening of a new garden in Paris, Reuters has pulled together a list of some of their favorite green spaces. Here are a couple of our favorites:
1. Paris, France. Who doesn't want to pull weeds with a view of the Eiffel Tower? This 150 square meter garden sits on top of the Palais de Tokyo museum. According to Reuters: "This temporary rooftop garden is a creation by three-star Michelin French chef Alain Passard who specializes in vegetable cuisine."
2. London, England. This is a covert operation: England's "guerrilla gardeners" (armed with seed bombs and pitchforks) plant flowers and herbs in "urban wastelands" under the cloak of night. "Their tactics are anarchistic," Reuters writes "their attitude revolutionary. Their aim: to beautify."
3. Paris, France. Well, they don't call it the city of gardens for nothing. This 30-meter vertical garden lives in the courtyard of Pershing Hall. It was designed by French botanist Patrick Blanc.
4. Torshavn, Faroe Islands. This government building keeps its carbon footprint relatively small by using grass as its rooftop material of choice.
5. San Francisco, California. This 2.5-acre "living roof" on top of the California Academy of Sciences houses native California plans. Inside, a natural history museum, aquarium, planetarium, and research facility offer some insight into what's growing above.
6. Mexico City, Mexico. More art piece than garden, "Not everything green is ecological" turns old VW Beetle taxis into lush bushes. It was created by artist Betsabee Romero and lived in a pond.