A purple glow illuminates stacked boxes where lettuce, herbs and kale will soon be sprouting at one of Europe's biggest "vertical farms" just opened in a warehouse in Copenhagen's industrial zone. Fourteen layers of racks soar from floor to ceiling in this massive, 7,000-square-metre (75,350-square-foot) hangar used by Danish start-up Nordic Harvest. The produce grown here will be harvested 15 times a year, despite never seeing soil or daylight but lit up around the clock by 28,000 specialised LED lightbulbs. IMAGES AND SOUNDBITES