Modular urban rooftop garden in Dublin uses only recycled materials

http://popupcity.net/2013/04/modular-urban-rooftop-farm-uses-only-recycled-materials/

Giant fish made from discarded plastic bottles collected form Botafogo beach in Rio de Janeiro, part of the UN Conference on Sustainable Development. 

(Source: thisiscolossal.com)

Canopy of recycled plastic bottles filled with coloured water by Garth Britzman in Lincoln, Nebraska 

(Source: thisiscolossal.com)