Some contend that the gold menorah from the Second Temple is hidden in the basement of the Vatican.
But according to Steven Fine, this is just an urban myth.1
While no one knows how the myth actually arose, Fine says that it "is not a part of traditional Jewish folklore." Rather, it is a "distinctly American phenomenon."
As for the menorah myth, he’s heard at least 10 to 15 variations of the story, which, he said, have been extremely popular since the 1970s. "I’m fascinated by these stories," he said, so he started following them in an effort to examine the historical material "through the lens of myth. I wanted to see where the path would lead," he said, calling his efforts "an interaction between the culture we live in now and people who died some 1,500 years ago."
Fine said the menorah myth, which apparently started in the United States some 30 to 40 years ago, "is not an easy story to refute. You can’t refute something when you don’t know who started it." link
"The Hebrew collection in the British Museum forms one of the greatest centres of Jewish thought. It is only surpassed by the treasures which are contained in the Bodleian Library at Oxford. The fame of these magnificent collections has spread far and wide. It has penetrated into the remotest countries, and even the Bachurim (alumni) of some obscure place in Poland, who otherwise neither care nor know anything about British civilisation, have a dim notion of the nature of these mines of Jewish learning.
All sorts of legends circulate amongst them about the "millions" of books which belong to the "Queen of England." They speak mysteriously of an autograph copy of the Book of Proverbs, presented to the Queen of Sheba on the occasion of her visit to Jerusalem, and brought by the English troops as a trophy from their visit to Abyssinia, which is still ruled by the descendants of that famous lady. They also talk of a copy of the Talmud of Jerusalem which once belonged to Titus, afterwards to a Pope, was presented by the latter to a Russian Czar, and taken away from him by the English in the Crimean war; of a manuscript of the book Light is Sown [ie, Or Zaruah] which is so large that no shelf can hold it, and which therefore hangs on iron chains. How they long to have a glance at these precious things! Would not a man get wiser only by looking at the autograph of the wisest of men ?
Solomon Schechter, "The Hebrew Collection of the British Museum," in Studies in Judaism First Series, pg. 252.
1 No kidding.