Everyone knows the image - the royal family waving from the balcony as planes fly overhead. But behind that balcony stands a building that's more a small city than a home. Buckingham Palace, on the day of its most famous ceremony, reveals how little we actually know about the place where decisions were made for half the world.

The numbers are almost unbelievable. The palace covers 77,000 square meters and has over 770 rooms. Inside there's a pool, a cinema, a cafeteria, a medical clinic, a chapel, a post office, and even an ATM - literally a city in a single building. There are also over 350 clocks tended by a dedicated staff, and a 16-hectare garden, the largest private walled garden in central London.

History is hidden in the details. Queen Elizabeth II lived there for 70 years, though she slept at the palace mainly when she had official duties the next day. King Charles III and Princes Andrew and Edward were born right there. And in 1982, a man named Michael Fagan broke in twice, once reaching the queen's very bedroom - one of the most famous security breaches in British history.

The palace is full of theatrical details: secret doors hidden in mirrors and furniture for the royal family's discreet entry, tunnels leading to other locations across London, and even an ancient underground river, the Tyburn, flowing beneath the building. It doesn't lack a ghost legend either - a "phantom monk" said to have appeared on the terraces.

The Trooping the Colour ceremony, with over 1,400 soldiers, 200 horses, and hundreds of musicians, is only the facade the public sees once a year. The real story is in the walls - in the splendor built to impress, in the tunnels built to conceal, and in the question every monarchy carries: how much does it cost to maintain all this, and who pays the bill in the end.