Quoting Google:
In May 2021, Italian artist Salvatore Garau sold an “immaterial” sculpture titled Io Sono (I Am) for €15,000 ($18,300) at the Italian auction house Art-Rite; the buyer received a certificate and display instructions for an empty 5×5 ft space.
Garau framed the work as a concentration of thought and energy—citing the Heisenberg uncertainty principle to argue the “vacuum” still has presence.
The piece sparked viral debate (and a threatened lawsuit from a U.S. performance artist who claimed prior “nothing” works).