Ragnar Kjartansson’s new performance for National Museum Cardiff, The Sky in a RoomHUGO GLENDINNING

If you walk into the National Museum Cardiff today, you will experience something quite strange and beautiful. The Icelandic performance artist Ragnar Kjartansson’s long-duration piece The Sky in a Room places a rotating series of organists at the museum’s 1774 Sir Watkins Williams Wynn organ. During museum hours, until March 11, they will constantly play on that historic instrument the 1959 hit song Il Cielo In Una Stanza, originally recorded by the Italian pop singer Mina.

The piece has been made possible by a £30,000 award from the Derek Williams Trust (as well as additional support from the Art Fund), which works with the Artes Mundi prize to allow the National Museum Wales to commission works from shortlisted artists (Kjartansson won the purchase award in…