ALONG the west bank of the Rhine, south of Frankfurt, cormorants and herons frolic as barges moor at Ludwigshafen. Here the world’s largest chemical park stretches out over ten square kilometres. Streets such as Chlor-, Ammoniak- and Methanolstrasse are shaded by 2,850 kilometres of pipes that connect everything like arteries; red is for steam, yellow for gas, green for water. The saying goes that
![Chemical reaction](https://cdn-ak-scissors.b.st-hatena.com/image/square/bd5bbe6051df5d54b095db4a35b25018325734ce/height=288;version=1;width=512/https%3A%2F%2Fwww.economist.com%2Fimg%2Fb%2F595%2F335%2F90%2Fsites%2Fdefault%2Ffiles%2Fimages%2Fprint-edition%2F20160917_WBP004_0.jpg)