The Immovable Ladder

Despite its name, the Immovable Ladder is a ladder that has been moved twice since it was first considered worthy of mention in 1757. It's located beneath a window at the Chruch of the Holy Sepulchre in Jerusalem and has become something of a symbol of the the longitudinal rift in Christianity since the Great Schism. You can read more about it here:
Immovable Ladder

Wikipedia's entry omits the indefinite article, implying that unlike Highlanders there can be more than one immovable ladder. In the event, the only claimed immovable ladder has moved twice in the last two decades. Nominally the ladder is immobile since any changes to the exterior of the Church of the Holy Sepulchre require the approval of the Eastern Orthodox, Oriental Orthodox, and Roman Catholic Christian orders, and Pope Paul VI declared in 1964 that the ladder shall not move until the schism between the Eastern and Western Churches is reconnected. Despite this order, the ladder briefly went missing in 1997 and was moved again in 2009 to help facilitate renovations to the church. Before anyone feels like cracking any jokes about Papal infallibility, the reader is encouraged to actually read what that particular dogma actually entails, and remember that nobody actually thinks that Popes are magical red-shoe'd oracles.

Chalk this one up to people forgetting that words have meaning.