I ran across this mention of this subterranean farm in an old bank vault under the busiest part of Tokyo . This blog explains how the farm works has has lots of great pictures showing the different grow rooms.
Though walled in from sunlight, weather and geology, it’s unbelievably verdant. Tomatoes, lettuces, strawberries, and other fruits and vegetables, as well as flowers and herbs, are grown in an area covering almost a square kilometer (!!!). There is even a terraced rice paddy.
This kind of farming can’t be an efficient use of energy, but interesting to see how urban farming experiments are taking shapes in other parts of the world.
actually if they used natural light from light tubes and/or fiber optics in con-junction with solar energy it would be energy efficient… if there is natural undergrouns water this would be a wonderful use of natural resources… given the location there should not be worries of bugs or rodents either or control thereof would be much easier….