Trooping the Colour procession along The Mall in London, England, on June 16, 2007

A royal birthday parade. Trooping the Colour

When your head of state has a birthday, you don't throw a surprise party. You summon the Household Division, clear the Mall and get the Red Arrows to write a message in the sky. Trooping the Colour is a centuries-old military tradition, held each June to mark the official birthday of the reigning monarch—even if their actual birthday is in, say, November. The real reason? The weather's better. No one wants to troop anything through puddles. There's marching, music, horses, salutes—and a good chance of spotting a royal in a bearskin or bonnet.

The name comes from 'trooping' (carrying) regimental flags—or 'colours'—through the ranks. It's all about honouring both the King and the regiments who serve him. Over 1,400 soldiers, 200 horses and 300 musicians take over Horse Guards Parade in London, showcasing the British Army at its best. The King inspects the troops; the Royal Family appears on horseback or in carriages and the RAF crowns the occasion with a spectacular flypast over Buckingham Palace. Whether you're watching in person or tuning in with a cuppa, it's a brilliant excuse to wave a flag.