I like thinking about alternative history. There are people like Harry Turtledove who write extensive alternative histories based on whether the South's main general's war plans got to the Northern armies' general in time for the Battle of Antietam. For me there's something appealing about thinking back through complex events in world history and finding critical moments and critical decisions that might have gone another way. I'm also quite taken with the idea that some historical events end up in hindsight looking like perfect storms, where a number of complex variables make the world we now know, but where any one of those variables would have produced a massively different result.

But I'm less interested in thinking about waving a magic wand to change the weather of some day or to change facts on the ground or morale or something like that. What I'm most interested in are situations where someone's individual decision might have dramatically altered the world. Can you identify one decision that happened in the past that you would have that person making it change? How might that set us up in a different reality?

A small note on housekeeping before I let you go. I know this might be a type of topic that walks the fence between something designed for ~talk and something best suited in ~humanities. I think of this as kind of an experiment to see how best to handle topics that straddle two different tildes.

I watched a documentary about Stonehenge tonight, and it proposed the theory that the location for Stonehenge was chosen because of a natural geological feature in the area.

There's a man-made path that proceeds south-west towards Stonehenge: "The Avenue". This path was built around the same era as Stonehenge itself. If you walk westward along The Avenue on the winter solstice, you'll be facing the point on the horizon where the sun sets. However, under The Avenue, there's an old natural geological formation from the time of the Ice Age: a series of ridges in the rock which just coincidentally align with the sunset on the winter solstice (an "axis mundi"). Before Stonehenge was built, there was a chalk knoll on that location. That meant that you could walk along a natural geological path towards the sunset on the shortest day of the year, and there was a local geological landmark in front of you.

The theory is that these natural geological formations coincidentally aligning with an astronomical phenomenon made the site a special one for early Britons. That's why there was a burial site there, and later Stonehenge was built there.

Here's the article by the archaeologist who discovered the Ice Age ridges: Researching Stonehenge: Theories Past and Present