Underland: A Deep Time Journey

by Robert Macfarlane

I wonder at what will remain of our cities as the Anthropocene unfolds over deep time – the stratigraphic markers that will endure in the rock record. Over millions of years, the inland megacities of Delhi and Moscow will largely erode into sands and gravels, to be spread by wind and water into unreadable expanses of desert. The coastal cities of New York and Amsterdam, those claimed soonest by the rising sea levels, will be packed more carefully into soft-settling sediments. It is the invisible cities – the undercities – that will be preserved most cleanly, embedded as they already are within bedrock. The above-ground structures we have built will collapse to form jumbled urban strata: medleys of concrete, brick and asphalt, glass compressed to a milky crystalline solid, steel dissolved to leave trace impressions of its presence.28 Below ground, though, the subways and the sewerage systems, the catacombs and the quarry voids – these may preserve their integrity far into a post-human future.