LONDON (AP) — Stonehenge monuments that have stood for thousands of years appear unscathed after climate protesters were arrested for spraying orange paint on them.

Nick Merriman, the chief executive of English Heritage, said workers cleaned the stones and the roughly 4,500-year-old monument was visibly undamaged.

The UNESCO World Heritage Site site reopened and was expected to host thousands of revelers celebrating the summer solstice, the longest day of the year in the northern hemisphere, early Friday.

A 73-year-old man and 21-year-old woman were released on bail Thursday after being arrested a day earlier on suspicion of criminal damage, damaging an ancient monument and deterring a person from engaging in a lawful activity.

The climate change activism group Just Stop Oil has taken responsibility.