A fascinating video released by the Royal Family shows the long route taken by butlers delivering food to some of Buckingham Palace's more remote rooms.
The footage shows how staff have to navigate a labyrinth of corridors in the world-famous building's basement and hallways to get the palace's Chinese Drawing Room, where functions are often held.
The video was released to show why new lifts are needed as part of the revamp being undertaken at the Palace in central London, reports the Daily Mail.
The Royal Family tweeted the video with the message: "Many of the lifts at the Palace are old and impractical - here's how staff currently navigate from the kitchens to the Palace's Chinese Drawing Room for functions.
"The route will be more practical & efficient when new lifts are installed."
Architectural lead Tony Barnard said the current route to the room, through the main corridors and past state rooms, is not practical and it would be better for staff to come straight up from the basement.
As well as aiding staff routes from the kitchens in the basement to the function rooms, the new lifts will make the building more accessible to wheelchair users.
Footage unveiled today also shows how architects have used 'Point Cloud' laser technology to map the building and make a 3D computer model to aid the redevelopment.
Point Cloud technology, which users lasers to scan and measure rooms, has been brought in to produce 3D computer surveys of around 400 rooms and 515 metres of corridor.
Architect Mr Barnard added: "Point Cloud surveying is a way to capture a really detailed image of the building that in turn allows us to have a level of information we've never had before.
"We can then use that information in a smart way to design the resurfacing and alterations we need to carry out to the palace."
The $712 million project began in April 2017. Costs will total $712 million and will be paid for by taxpayers via the Sovereign Grant, the annual fee paid by the Government to the monarch which in 2016 came to $81 million.
The work, which began in April last year, is due to be completed in 2027.
A statement posted on the Royal Family's website today says: : "The Palace's electrical cabling, plumbing and heating have not been updated since the 1950s. The building's infrastructure is in urgent need of a complete overhaul to prevent long-term damage to the building and its contents.
"The most cost-effective way to replace these essential services, and to ensure that The Palace is fit for purpose for the next 50 years, is to undertake a phased programme of works over ten years.
"The programme will realise a series of long term financial and environmental benefits, as well as improvements to visitor access. The Palace will remain occupied and fully operational for the duration."
Renovation work hopes to bring the palace up to scratch and ensure that it is fit for purpose for the next 50 years.
The renovation work is a huge task as the palace has 775 rooms, 1,514 doors and 760 windows, alongside a hundred miles of electrical cabling.
The Sovereign Grant, which comes from general taxation, will be hiked up during renovation period to cover the costs.
The Queen currently gets an amount which is equivalent to 15 per cent of the profits from the Crown Estate, but this will increase to 25 per cent.
Previously the Master of The Queen's Household Tony Johnstone-Burt said: "We take the responsibility that comes with receiving these public funds extremely seriously indeed.
"Equally, we are convinced that, by making this investment in Buckingham Palace now, we can avert a much more costly and potentially catastrophic building failure in the years to come."
It is estimated that the benefits of the upgrade, including longer summer opening hours, more private tours and savings due to the improvements, could be around $6.5 million each year.