From Swamp To Sponge: Berlin Harnesses Rain In Climate Shift

The reservoir, 40 metres in diameter, will collect almost 17,000 cubic metres of water (Credit: AFP)

In two years' time, a massive hole in the heart of Berlin will become the German capital's biggest reservoir, capturing an increasingly precious resource -- water.

Once a swamp centuries ago, Berlin has gone from a city trying to keep its abundant groundwater from overflowing to one scrambling to keep its forests green.