Royalty Monte Carlo.18th March.1968. Prince Rainier of Monaco and his wife Princess Grace dance the first waltz at a ball to mark the grand opening of the refurbished casino. [Getty Images]

Royalty, Monte Carlo,18th March,1968, Prince Rainier of Monaco and his wife Princess Grace dance the first waltz at a ball to mark the grand opening of the refurbished casino (Photo by Bentley Archive/Popperfoto via Getty Images/Getty Images)

Popperfoto Bentley Archive/Popperfoto