Beyond digital art, there’s conceptual art. In 2021, the “Io Sono” artwork (which translates to “I am”) by Italian artist Salvatore Garau was sold for almost €15,000. What’s so special about it, you ask? It’s invisible. The lucky buyer was given a certificate of authenticity and... nothing else. “An intangible sculpture to be installed in a private residence” said the catalogue listing before the auction, it was said to measure around 1.5 x 1.5m and “will be perfect in any space free from clutter”. Well... at least moving house won’t be an issue.