During a summer vacation in Italy in 2012, Sergio Gamberini was struck with an idea: why not try to grow basil underwater? Crazy as it sounds, the diving aficionado was onto something.

Given the right temperature, humidity and illumination, certain plants would thrive in an underwater lab. If it worked, this method could help arid countries grow more crops at a lower cost. So, Gamberini made some calls and started sinking biospheres 20 feet deep in the sea off Noli on the Italian Riviera. The first five biospheres of Nemo’s Garden were arranged in a pentagon around a central hub. Each of them holds about 2,000 litres of air, and as the sunlight warms the air, fresh water condenses on the walls which is then collected to water the plants.