On Christmas Day 1833, Charles Darwin and the crew of HMS Beagle were larking about at Port Desire in Patagonia, under the keen gaze of the ship’s artist, Conrad Martens.

The crew were mostly young men – Darwin himself, a recent graduate from Cambridge University, was only 22 – and had been given shore leave. Martens recorded them playing a naval game called Slinging the Monkey, which looks much more fun for the observers than the main participant. It involved a man being tied by his feet from a frame, swung about and jeered by his shipmates, until he manages to hit one of them with a stick, whereupon they change places.