This gravel was scooped up and poured into setting concrete. I wonder if the pebbles are siblings from the same lake, river or ocean bed.

Concrete is like a part of London's flesh. So familiar, and a large part of the rubble that makes up the Phytology midden. Our era will be known by the vast amount of concrete that we leave behind, and this material only gets stronger as it gets older. Concrete has become the second most consumed substance in the world, behind water.