I admit that I like to play practical jokes, and the more people affected the better.
So, my devious evil mind came up with a plan to mess with people 500 years from now.
First, let me point out a few things that will make this plan work.
1) Three of the world's supervolcanoes are showing increasing signs of activity. Or to put it simply, everything that happened before St. Helens blew up, is happening at these three calderas.
The main difference is that if one of these go boom, we have a volcanic winter that will last 8 to 20 years, followed by an ice age.
2) The kind of global devastation will be such that for the most part, civilization will collapse.
Now for the plan.
Various stone suppliers in England and Europe can provide stone that was initially quarried in the middle ages. Other firms can supply recycled timbers, beams etc from middle ages buildings.
With those construction materials, a large Middle Ages town, complete with castle, a monument like stonehenge, and all the supporting industry is constructed.
Old growth European Oaks, and other hard wood trees are imported to landscape the area, along with large numbers of English wildlife.
Finally, well trained scribes will create a written history (pre printing press) for our nice little town.
After the Volcanic winter and the recovery period, your basic scholar types will be out trying to assess the impact of the eruptions.
Suddenly they come across a middle ages town, no modern technology, and people who state emphatically that they are in England, but due to some "Act of God" or magic, they cannot seem to figure out just where they are. (of course our citizens know the joke)
Now every historian, archeologist and physicist will be trying to solve a mystery that doesnt exist.
Meanwhile, our citizens are laughing out there collective minds.
