SolFire writes "The BBC is running a look at the potential for Vertical Farming in the Big Apple, a concept that promises to reduce the environmental impact of farming and increase the efficiency of food production by building multi-story farm complexes in urban areas. The vertical farm is envisioned as a self sustaining complex of greenhouses stacked on top of each other. More details can be found on the project web site."
I've never been canoeing before, but I imagine there must be just a few
simple heuristics you have to remember...
Yes, don't fall out, and don't hit rocks.