A No Sharp objects warning is plain to see as a British Airways check-in employee attaches a luggage tag to the suitcase of a Business Class passenger about to take a long-haul flight from London Heathrow Airport's Terminal 5. The bag is about to disappear down the conveyor belt to join up to 70,000 other items during this average day at T5. With a bar code to identify both the bag and its owner's destination as well as the three letter IATA code, the bag enters 11 miles of underground conveyor belts beneath the 400m (a quarter of a mile) length of Terminal 5 at Heathrow Airport. T5 alone has the capacity to serve around 30 million passengers a year and was completed in 2008 at a cost of £4.3bn. From writer Alain de Botton's book project "A Week at the Airport: A Heathrow Diary" (2009). .