City Gardens

The Sheraton Hotel in Denver Partnered with a Spanish firm and the Mile High Gardening Conference to create a 16 x 20 ft. wall of plants next to the entrance. This garden is not so much of a sustainable matter as is, but shows how people could easily grow gardens in the city on rooftops. These green roofs are an up-and-coming trend to help filter the air in cities and to provide fresh, organic produce for building occupants.

http://inhabitat.com/sheraton-vertical-garden-built-for-mile-high-gardening-conference-in-denver/