Robert Smithson’s legendary “Spiral Jetty” is once again visible just off the shore of Utah’s Great Salt Lake. As the world’s most prominent example of the Earth Art movement, the piece is attracting visitors from around the world. “It is, however, strangely changed. Three decades of immersion have coated the dark rock with sparkling salt crystals, so the Jetty and its surroundings now resemble a landscape from the frozen north. The rich, rusty waters coloured by moulting shrimp and algae have now turned pale pink. All of this poses a neat conservation dilemma for the Dia Centre for the Arts, to which the Spiral Jetty was donated in 1999.”