Sketches of Stonehenge have been found in a 15th century manuscript. 

There are two earlier images of Stonehenge, one in the British Library and one in the Parker Library in Cambridge, but the Douai drawing is unique in attempting to show how the monument was built.

It correctly shows tenon joints piercing the lintel, a timber construction technique, although in fact the real Stonehenge tenons only go partly into the top stone.

The drawing will be exhibited next year at the Royal Academy in London during the 300th anniversary of the Society of Antiquaries.

[via reddit]