A mason doing restoration work at the Church of the Holy Sepulchre (i.e. the church built over the place where it is claimed Jesus was buried) accidentally left a ladder behind, sometime before 1728 when it shows up in an engraving of the building. Because the six Christian groups who control the site cannot agree on what to do with it, it is still there today.
To read more on the background of the Status Quo, you could go to Wikipedia.
To see more photos, and some video of the physical fights the groups occasionally get into for various reasons, you could go here.