The small chapel in the Village of Roslin just south of Edinburgh has stood since the 1450's. Following the reformation in 1560, it was the private church of the local feudal lords, the catholic Sinclair family, before becoming a public episcopalian church in 1861. Since the 1980's it has been the subject of religious and historical conjecture about the Holy Grail (the cup Jesus was supposed to have used at the Last Supper), freemason conspiracies and the secret medieval group called the Knights Templar.
The chapel is elaborately decorated with 1000's of intricate carvings depicting strange and wonderful figures and scenes, but their meaning has long been forgotten. Several members of the Sinclair family have been senior members in the Freemasons over the centuries and there is an intricate and beautiful '[Ap]prentice pillar' in the church (more than likely this was originally the 'Prince's Pillar' but because of the association with Masons, the name morphed). All of these things have contributed to the myths surrounding the history of the church culminating Dan Brown's 2003 book 'The DaVinci Code' making it the place for secret clues to where the Knights Templar hid the Holy Grail.
An earlier idea promoted in the 1980's Book: The Holy Blood and the Holy Grail, was that Jesus had offspring with Mary Magdalene and the Sinclair family were his direct descendents. Of course all of this weird history is bunk. The church is a charming and fascinating building and worth a visit, the real history is much more prosaic but nonetheless fascinating.