Part of Stonehenge has been covered in orange powder paint by protesters.
Two Just Stop Oil campaigners sprayed the powder paint on the historic site near Salisbury, Wiltshire, at about 12:00 BST on Wednesday.
The move comes the day before celebrations begin for the Summer Solstice at the 5,000-year-old landmark.
Wiltshire Police confirmed two people had been arrested on suspicion of damaging the ancient monument.
Just Stop Oil said the orange powder paint was cornflour and it would “wash away with rain”.
The group named the two protesters as Niamh Lynch, a 21-year-old student from Oxford, and Rajan Naidu, a 73-year-old from Birmingham, in a statement.
