In 1728, a mason left a ladder by accident in the Church of the Holy Sepulchre in Jerusalem. It is still there today. This so-called "immovable ladder" can't be moved because any changes to a Christian site in the Holy Land require the approval of six different Christian communities under the so-called "status quo".
https://en.wikipedia.org/wiki/Status_Quo_(Jerusalem_and_Bethlehem)