A long time ago I read the Arthur C Clarke short story The Sentinel.   It was the inspiration for the film 2001: A Space Odyssey and formed the first act.  In the story a structure of incalculable age was found on the surface of the moon.  The story ends with the transmission of a signal out into space – although Wiki suggest more but I cannot recall that.

This book flashed back into my mind this afternoon as I clambered over the rocks of Beacon Hill in Leicestershire.   This time the structure’s age – less than a hundred years.  However the age of the Precambrian rocks that it is sitting on are incalculable.  Actually that is not true as their age is known to around 561 million years, but they are some of the oldest rocks anywhere on the surface of the earth.  So unlike the structure sitting on the surface they have seen the rise of life on earth and no doubt will still endure long after we humans have passed into dust to be replaced by what no one can know.