The UK has begun a four-day celebration of the Queen's Platinum Jubilee, marking 70 years on the throne. Elisabeth II, now 96, acceded the throne aged 25 and is Britain's longest-reigning monarch.
To mark the occasion, events have taken place across the UK this year, culminating in a four-day weekend of celebrations, starting on Thursday.
Festivities got underway at 10:00 British Summer Time, with the Queen's birthday parade, also known as Trooping the Colour. The Queen and members of the royal family then made an appearance on the balcony of Buckingham Palace, their London seat, before the event ended with planes doing a fly-past. Later on Thursday, 1,500 beacons will be lit across the country.
In a Jubilee message, the Queen thanked the public for organising the events and said she was "inspired by the goodwill."
Buckingham Palace released an official photograph of the Queen for the occasion.
As millions join in the celebrations, crowds have descended on London with people camping on the Mall overnight to get a good viewpoint.
The Trooping the Colour parade involves over 1,500 officers and soldiers and 350 horses from the Household Division.
The 96-year-old monarch has finally started to feel her age and recently cancelled several public appearances. However, she will be present for many of the events in the coming days.
Prince Harry and Meghan Markle flew over from the US to join the celebrations. The couple will watch the parade, but will not appear on the balcony. Their children, Archie and Lilibet, are with them.
Prince Andrew, the Queen's son, will not be present after being the subject of a protracted lawsuit in the US that saw him stripped of his royal titles.
Events marking the anniversary this weekend will include:
Friday 3 June:
- Service of Thanksgiving at Saint Paul's Cathedral
Saturday 4 June:
- A Platinum party at Buckingham palace featuring a performance by Diana Ross
Sunday 5 June:
- A Big Jubilee gathering at lunch, with ten million expected to take part in street parties
- A London pageant, a military parade, giant puppets and a performance by Ed Sheeran
Royal families across Europe
While the UK has the most well known royal family, there are still 12 royal families in Europe.
Seven countries are still kingdoms: Norway, Sweden, Denmark, the United Kingdom, Spain, the Netherlands, and Belgium. Andorra, Liechtenstein, and Monaco are principalities, while Luxembourg is a Grand Duchy.
These countries are constitutional monarchies, in which the monarch acts as a non-party political head of state under a constitution. While constitutional monarchs may hold some authority, it is the democratically-elected governments that decide public policy or choose political leaders.
By contrast, a republic, such as France, is a form of government in which power is held by the people and their chosen representatives, rather than families that inherit power.
The Belgian royal family
In Belgium, King Philippe ascended to the throne in 2013 after the abdication of his father Albert II. King Philippe rules alongside Queen Mathilde, who he married in 1999.
King Philippe was born in 1960 and attended both French and Dutch language schools during his upbringing. He attended the Royal Military Academy in Belgium and studied politics at Oxford University and Stanford University.
The couple has four children: Princess Elisabeth, Duchess of Brabant, Prince Gabriel, Prince Emmanuel and Princess Eléonore. The eldest, Princess Elisabeth, was born in 2001 and will one day succeed her father on the Belgian throne.
Belgium has had a monarchy since it became independent in 1830.