Even museums are not safe places for ancient art, it seems (BBC, "Waiter knocks thumb off Roman sculpture at British Museum" 27 October 2016 )
A waiter working at the British Museum knocked the thumb off a priceless Roman sculpture, it has emerged. The accident occurred in December last year, according to The Art Newspaper, but has only just come to light. The waiter, who was from an external company, had bent down underneath the Townley Venus and knocked its right hand while getting up again. The thumb was knocked clean off the statue and fell to the floor intact. The statue has now been restored.[...] The sculpture, which depicts a half-naked figure of the goddess of love, is a marble copy of the Greek original and dates from the 1st or 2nd Centuries. It was excavated in 1775 from the baths at the port of Ostia in Rome and bought by English collector Charles Townley. It was sold to the British Museum in 1805. The Greek original dates back to the 4th Century BC.