Like most other weddings in history, all British royal weddings begin with - the engagement.
But unlike regular weddings these ones involve an elaborately choreographed event that'll
be watched by an audience of millions.
One of the first decisions a couple makes is deciding where to actually do the thing.
If they're really into history and tradition, there's really only one choice - From the
solemnity of the abbey...
But not this time.
The big change is this wedding, between Prince Harry and Meghan Markle, and you don't have
all the ambassadors from all the different countries, you don't have heads of state coming
to this wedding.
One reason is because the chapel at Windsor can only take 600 people, and therefore there
simply isn't the space.
But it's also clearly the desire of Prince Harry and Meghan Markle to have a more informal
wedding.
Around two months before the big day, the Lord Chamberlain's office sends out individually
crafted invitations.
There's flowers and fittings, and the entirety of the city to prepare.
While the bride and groom had to sleep in different homes, spectators who want to have
a decent view of the public processions will be sleeping outside.
And just a few hours later...
Some travelled hundreds or even thousands of miles and they camped out overnight to
get a prime position along that procession.
The general rule of royal weddings is the less important you are, the earlier you arrive,
and the further back you sit.
If you're there representing a charity, if you're a member of the armed forces, or a
celebrity, you're relegated to the nave of the church, which means you might not even
get to see the actual ceremony.
Close friends of the bride and groom and other guests will head in at least an hour and a
half before.
Most of the time it is - groom up at the front, the royal procession comes in order of precedence,
which means the more junior royals come first.
And last comes the Queen and her husband, Prince Phillip.
Lots of fanfares as they come, and then the bride turns up.
When the the bride arrives, the details of the dress are finally revealed after months
of top secrecy.
I am beside myself.
This is such a fashion moment - I can't tell you.
And regardless of who the designer is, she'll be wearing white and will carry a sprig of
myrtle in her bouquet, which symbolises love and marriage, both of which are trends started
by Queen Victoria.
The bride's tiara is almost always the 'something borrowed'.
Likely from one of the family's collection of jewels.
Since 1923 the ring placed on the bride's finger is always made from Welsh gold.
Elizabeth and Diana's rings even came from the same nugget.
The ceremony's performed by the Archbishop of Canterbury, and only takes about an hour.
Towards the end, the bride, groom and their two witnesses go into a private room to sign
the register.
At that point the wedding is sanctified in law, as it was sanctified by religious service
a few minutes previously.
Officially married, the bride and groom exit, closely followed by the procession of the
Queen.
If there's any heart that hasn't been won over today, it can kindly surrender now.
There's a good chance you'll hear Pomp and Circumstance around this time.
Although Americans associate it with high school graduations, it was originally written
for the coronation of King Edward VII.
The bride and groom will likely make their way into the open 1902 state landau, for the
official carriage procession around the city.
That's when the crowds, who have been waiting for hours, or possibly days, will get their
first look at the royal couple.
This usually concludes with the iconic appearance on the Buckingham Palace balcony, on which
Diana and Charles were the first to kiss.
The kiss is a critical moment in the entire royal wedding ceremony.
You don't just throw it away in the middle of church.
It has to be seen live by hundreds of thousands of people.
And just in case anyone had missed it, Prince William suggests - one more kiss.
Because Meghan and Harry's wedding is 20 miles outside of London, their first public kiss
as a married couple will have to happen somewhere else.
Afterwards, the wedding party takes official photos and ceremony guests gather for the
wedding breakfast, complete with the traditional fruit cake.
Though, in the past, the bride and groom would change clothes and depart for their honeymoon
directly afterwards, current royals have gone for a more modern approach with a real party.
And they won't be the only ones celebrating.
It's generally seen as an excuse to have a good time and, somewhat buttoned up Brits,
who don't really have a good time in public that much, let their hair down and enjoy themselves
in the middle of their street.
At that point it's a pretty normal wedding reception, although normal ones don't generally
include rumoured performances by Elton John and the Spice Girls.
The royal couple will head off for the honeymoon, which is almost certainly within the British
Commonwealth, while the rest of the country...
nurses a hangover.
As they leave far behind them an exhilarated, exhausted London, for them, as for any newly-weds,
the adventure is just about to begin.