Just because you're six stories up and the closest thing to a balcony you've got is the fire escape, doesn't mean you can't have yourself a kick-ass herb garden. The Volet Végétal concept could give even the densest city dwellers access to a little greenery.
The Volet Végétal—"plant shutter"—was conceived by French design firm Barreau & Charbonnet as a submission to Jardins Jardin exterior design expo in Paris. The device's outer frame mounts on the interior of a window frame and supports an inner three-row frame of planters. This inner frame swings down, like a drawbridge, as slack is let out in cables attached to the upper edges of the inner frame. This allows the plants to get more sun during the day and be hoisted in during inclement weather or at night. It also triples the amount of windowsill space available for growing. The only immediately foreseeable issue is a maximum allowable plant height. [Barreau & Charbonnet via Treehugger - Gif: Barreau & Charbonnet]