Four days of celebrations honouring Queen Elizabeth II’s 70 years on the throne kicked off Thursday with a display of British military traditions stretching from the days of horse and cannon to the jet age.

Thousands of people, some of whom camped overnight, lined the parade route — many of them sporting Union Jack flags, party hats or plastic tiaras. Carly Martin, who caught a late-night bus from south London with her daughter, said she had come “to make memories.”

The 96-year-old queen is Britain’s longest-reigning monarch and the first to reach the milestone of seven decades on the throne. Elizabeth smiled broadly Thursday as she spoke with her great-grandchildren and looked up as the British military aircraft roared over the palace. The six-minute display included Typhoon jets flying in a formation spelling out the number “70.”

The jubilee is being commemorated with a four-day holiday weekend. The celebration of Elizabeth’s reign includes a service of thanksgiving on Friday at St. Paul’s Cathedral in London, a concert at Buckingham Palace on Saturday and a pageant staged by thousands of performers drawn from schools and community groups around the country on Sunday. Thousands of street parties are planned around the country, repeating a tradition that began with the queen’s coronation in 1953.

The jubilee is giving many people — even those often indifferent to the monarchy — a chance to reflect on the state of the nation and the huge changes that have taken place during her reign. Former Prime Minister John Major — one of the 14 prime ministers of the queen’s reign — said the monarch’s stoic presence had helped steer the country over the decades.