Urban greenery specialist GWS Living Art has installed green roofs on 10 public buses in Singapore. The "Garden on the Move" campaign is part of a trial to see whether plants can help to reduce the temperatures inside buses so that operators can save the fuel that is spent on air conditioning.
The plants are succulents and grasses that have been specially selected to withstand warm conditions on top of the buses.
The same technology has been used in other parts of the world, including this bus stop in Kuala Lumpur, Malaysia. The plants reduce the temperature and purify the air around the bus stop, as well as providing a home for city wildlife. According to GWS LIving Art, the bus stop can survive 7-10 days without water.
As more cities are trying to incorporate greenery into urban living, green roofs have been sprouting up in different places, bringing with them benefits such as reducing flood risk, cooling buildings and providing places for nature to thrive.
Beehives in England can be found on top of iconic buildings such as St Paul's Cathedral and luxury department store Fortnum & Mason.
In 2015, a panel of UK urban experts predicted that cows will be grazing on top of London's skyscrapers by 2100.