Queen Margaret II - 50 years for Denmark
She became head of an old royal house in a modern era. Royals and heads of state tell of unique meetings with a popular monarch.
Bill Clinton and our own King Harald and Queen Sonja are among the many the Queen has made an impression on.
Sweden's King Carl Gustaf and Queen Silvia and Iceland's Vigdís Finnbogadóttir are among those who often share their stories about Queen Margrethe.
