When I opened Janet Rudolph’s fascinating Spring 2025 collection of essays for Mystery Readers Journal—this edition her second on the theme of “London Mysteries,” I was delighted to discover the first one, by Aubrey Nye Hamilton, was “The Lost Rivers of London.” This was a happy coincidence, because my mystery book club this week was set to discuss Rivers of London: Midnight Riot, a 2011 book by Ben Aaronovitch that I listened to a few years ago.

This was one of those books I would never have chosen if I’d realized what it was about, but which I enjoyed immensely—despite myself, you might say. There has been a new book in the series every year since (plus a second in 2011), bringing the series total to 14 so far. I’ve not read another of these urban fantasies, but I did enjoy the first. In it, an apprentice wizard (and London police constable) must figure out why ordinary people are becoming vicious killers, as well as try to broker a peace between two warring gods of the River Thames and their respective families. I recall that the several River gods and their watery relatives were quite entertaining.

Hamilton’s essay describes the 600 km network of rivers that flows mostly invisibly, but sometimes audibly, beneath the city. They are the numerous tributaries of the Thames, and the River Fleet (yellow on the map), for which Fleet Street is named, is the largest. As author Melinda Mullet notes in her MRJ essay, the Charlbert Street Bridge (pictured above) is actually an aqueduct whose enclosed iron pipes carry water from the “lost” Tyburn River (purple on the map) to the lake in Regent’s Park.

Paved over and channeled into drainage pipes, the city’s “lost rivers” now aid its sewage and flood protection systems. Nevertheless, Hamilton notes, “sections of the sewer are often relatively dry and quite safe, if unpleasant, to travel.” This has made it possible for people, for whatever reason, to walk the city easily and invisibly, underground. As this and other essays in the volume attest, crime fiction writers have taken full advantage of this urban feature. In recent years, considerable effort has been directed to restoring and revitalizing these watercourses.

The map shows the lost rivers in color. The white squiggle is the River Thames. Perhaps they do all have distinctive personalities like author Aaronovitch speculates. The currents below the surface.