For as long as people have loved beauty, spending, and indulging their passions, those who could afford it have turned to collecting.

Rising demand from the world’s growing super-rich has caused sharp rises in the price of high-value collectibles, from art, classic cars, watches and jewellery to fine wine and whisky. Private enthusiasts have been joined by professional investors, spurred by more than a decade of cheap money following the financial crisis, for whom investment gains trump exhibition or use.

This, and the growing risk of theft of collectibles, has made collections less visible — enjoyed by fewer people and more seldom. Once displayed in private homes, at public art galleries or at enthusiasts’ events, many of the world’s most beautiful and valuable objects are today gathering dust, out of view, in secure underground storage vaults.