Watch the Changing of the Guard at Buckingham Palace, London
Music reaches the crowd before the formation does: drums and brass moving along the Mall, boots settling into rhythm and red tunics appearing between raised phones. Then the ceremony gathers itself against Buckingham Palace's gates. Check the Household Division's official calendar close to the day because duties, times, music and cancellations change. Arrive early enough for a lawful public viewpoint, but understand that no free pavement position guarantees an uninterrupted view. Keep bags secure in the crowd, leave crossings and entrances clear, follow police and steward instructions and prepare for sun or rain. Step-free pavements exist around the area, but density and sightlines vary, so plan a quieter nearby troop movement if that serves you better. Count it complete after seeing the official guard-change ceremony or its full troop movement at Buckingham Palace, not merely a sentry at a gate. Add it if you want history to arrive not as an exhibit, but as sound, precision and public ritual unfolding in the street.