They are among the most recognisable women in Europe - and lend more than a touch of glamour to its Royal families. But not all of them were born in the lands they now help rule.
Some of the most high profile guests at Westminster Abbey will be fellow monarchs from around the world, including King Felipe of Spain and Japan s Emperor Naruhito.
The Netherlands will pay tribute to those who have been killed during war and peacekeeping missions since the outbreak of World War II with ceremonies and a moment of silence on Thursday. The annual Remembrance Day is most notable for the national commemoration on Dam Square in Amsterdam, when a trumpet player’s music brings in the start of a two-minute moment of silence at 8 p.m. that is respected across the country.