LONDON (AP) — Queen Elizabeth II stepped gingerly onto the Buckingham Palace balcony Thursday, drawing wild cheers from the tens of thousands who came to join her at the start of four days of celebrations of her 70 years on the throne.

Elizabeth, who became queen at 25, is Britain’s longest-reigning monarch and the first to reach the milestone of seven decades on the throne. She basked in her moment. Smiling, she chatted with her great-grandson Prince Louis, 4, who occasionally covered his ears as 70 military aircraft old and new swooped low over the palace to salute the queen. The six-minute display included a formation of Typhoon fighter jets flying in the shape of the number 70.

Cheers and the clop of hooves rang out Thursday as horse-drawn carriages carried members of the royal family, including Prince William’s wife, Kate, and their children Prince George, 8, Princess Charlotte, 7, and 4-year-old Prince Louis, from Buckingham Palace to Horse Guards Parade, a ceremonial parade ground about 1 kilometer (0.6 miles) away, for the Trooping the Color ceremony.