The right way to do any social work is to work until you're not needed anymore.
Along with all the other stunning statistics China can provide, it can also claim to be the world leader in making energy from human excrement. Biogas, as this energy is known, can be produced from the fermentation of any organic material, from wood to vegetables to human excreta.
Half of the hospital beds in sub-Saharan Africa are filled with people suffering from what are generally known as water-related diseases.
I find Suez astonishing for the first hour. It is a ditch in a desert, but a stunning one. The sensation of being hemmed in by huge ships, moving at a stately pace through a man-made waterway, is extraordinary.
The more ships have grown in size and consequence, the more their place in our imagination has shrunk.
Before containers, transport costs ate up 25 percent of the value of whatever was being shipped.