Some 20% of all countries are still governed by a monarch of some kind - what makes monarchy so resilient?
There is a festive air in London, as the city prepares for the spectacle of a Royal Wedding at the end of this month - we are devoting this week's Forum to a look at where Kings and Queens fit in to our modern era.
Is there still such a thing as a bond between sovereign and subject? Do modern monarchies need to update themselves? Or is the link with history the key to staying popular?
Bridget Kendall is joined by Bangladeshi writer Tahmima Anam, British historian Justin Champion and Australian psychologist Dorothy Rowe.
Illustration by Emily Kasriel: The Prince ceremoniously marries a commoner, touching his subject and backed by generations of monarchs before him.
We take a look at Kings and Queens and ask where they fit into our fast changing century.
Kings and Queens and their relationship with their subjects.