Located on a golf course in Summerlin, an exclusive master-planned community in Las Vegas, this six-bedroom, 11-bathroom Tuscan-style mansion is simply divine. According to the Las Vegas Review-Journal, the former owner spent just shy of an incredible $20 million (£15m) fixing up the trophy home, sparing zero expense on all manner of high-end fixtures and fittings.

The library is equally upscale. A ravishingly sophisticated space, it wows with gilded wall panelling, bespoke cabinetry, antique crystal chandeliers and a fireplace that wouldn't look out of place in the Palace of Versailles. Other highlights include a dining room with a vast $85,000 (£65k) table, an office, home cinema, gym, smart home automation and a state-of-the-art security system.

A primary bedroom suite fit for Marie Antoinette is the cherry on the cake. Sadly, despite ploughing almost $20 million (£15.2m) into the property, the former owner struggled to sell it. Having originally listed the house in 2015 for $22 million (£16.7m), the homeowner ended up putting it into a closed auction earlier this year. It reportedly sold for around $5.6 million (£4.3m), meaning the lucky buyer pretty much got the bargain of the century.

Disaster befell the Texas Governor's Mansion in Austin one fateful morning in June 2008 when an arsonist threw a Molotov cocktail on the front porch, setting fire to the historic building and almost razing it to the ground. The perpetrator has never been found, leading the local Fire Department to describe the blaze as one of the greatest unsolved crimes in the history of the Lone Star State.

Needless to say, the mansion, which dates from 1854, was in an appalling condition following the fire, but the Governor Rick Perry and First Lady Anita Perry vowed to restore the residence to its former glory. The project was overseen by the State Preservation Board and Texas Historical Commission – and funded by a $21.5 million (£16.4m) grant provided by the legislature – as well as $3.5 million (£2.6m) from corporate donors and members of the public.

Fortunately, the mansion was undergoing a refurb at the time of the fire meaning many of its treasures including a desk belong to Father of Texas Stephen F Austin were in storage and therefore undamaged by the inferno. Shown here is the elegant front parlour post-renovation, the room in which the Governor and First Lady welcome guests.

The State Dining Room, which boasts a magnificent 18th-century table, was also restored sympathetically. In fact, all historic rooms in the mansion were recreated exactly as they were before the blaze. In addition, the building was fitted with new electrical wiring and a fire suppression system, and made accessible to people with disabilities.

This image shows the Sam Houston Bedroom, one of two historic bed chambers. Its most esteemed piece of furniture is the four-poster bed purchased by Texas' seventh governor, Sam Houston, from which the state's largest city takes it name. In total, the restoration was four years in the making with Perry and his family finally moving back into the mansion in July 2012.

German Catholic Bishop Franz-Peter Tebartz-van Elst earned the moniker 'the Bishop of Bling' and got into hot water with the local diocese and Vatican in 2013 when he spent a staggering $34 million (£26m) on a luxe revamp of his official residence and office, this extraordinary building located in the town of Limburg in Hesse, Germany.

Costing over six times the original estimate, the final bill for the makeover wasn't initially disclosed by the bishop to the diocese, who were up in arms over its indefensible extravagance. In sole control of the cash flow, Tebartz-van Elst secretly dished out millions of euros to architects and contractors, who certainly didn't hold back.

A slick minimalist building was constructed behind the original 16th-century presbytery packed with every mod con imaginable and jaw-dropping luxury extras. Among the refurb's many super-luxe features are a private chapel costing $3.4 million (£2.6m) and a Japanese koi carp breeding pond, which ended up setting back the diocese a cool $251,000 (£191k).

The conference room was decked out with a table worth $29,400 (£22k) and iPads were fitted to many of the walls in order to operate the building's various smart automation features, which include closing the curtains remotely and even calling up a prayer. 

The bishop's bathroom is equally slick with its $17,700 (£13.5k) freestanding spa bathtub and wellness shower. When the profligate expenditure finally came to light, Tebartz-van Elst was banished from the diocese, resigned his position and quietly assumed a low-profile administrative role in the Vatican City. 

One of England's grandest stately homes, Chatsworth House in Derbyshire is, as you might have expected, exceedingly expensive to maintain. The seat of the Cavendish family since the mid-15th century, the storied stately home recently underwent a renovation costing more than $42 million (£32m).

The most comprehensive upgrade of the 300-room house for two centuries, the refurb took almost 10 years to complete. Everything from the roofing and the turrets to the masonry was reconstructed, 1,500 sheets of gold leaf were used to re-gild the window frames, while a plethora of priceless antiques and artworks were meticulously restored by Britain's foremost conservators.

Overseen by the current custodian, Peregrine Cavendish, 12th Duke of Devonshire together with his wife Amanda Cavendish, 12th Duchess of Devonshire, the makeover was prompted by a major survey conducted in 2004 that identified myriad structural problems that were in dire need of being rectified. Shown here is the magnificent Painted Hall restored to its former glory.

Among the artworks restored is Maria Cosway's celebrated painting of Georgiana Cavendish, 5th Duchess of Devonshire, which was covered in layers of grime that had accumulated over the centuries. The work revived the picture's vivid colours and luminosity, as this before and after shot shows.

The Chatsworth House Trust also released this before and after image of the Minerva statue, which stands triumphantly atop the roof. The Cavendish family isn't resting on its laurels however, and is planning to spend a further $66 million (£50m) restoring properties and land on the wider Chatsworth Estate during the coming decade.

Templeton House, which is located in the leafy London suburb of Roehampton, dates from 1786 and was once home to Sir Winston Churchill. Over its long history the Grade II-listed Georgian villa has served as a hospital during both World Wars and later as a halls of residence for students at Roehampton University, but fell into disrepair during the early 21st century.

The tired mansion was eventually snapped up in 2010 by the appropriately named property developers David and Laura Rich-Jones for around $7.3 million (£5.5m) and the couple set about revamping the historic villa. Described by Architectural Digest as one of the UK's most painstaking projects in recent history, the restoration was 10 years in the making and cost more than $42 million (£32m). 

Great care and attention were taken to revive the dilapidated dream mansion. The Rich-Jones' hired a formidable team of researchers, artisans and design supremos to execute the transformation, from historian and landscape architect Todd Longstaffe-Gowan and heritage buildings expert Bob Sanford to a Farrow & Ball paint expert and master carpenters from top Derbyshire window firm Gowercroft Joinery. 

The couple called on the iconic Wedgwood company to restore the damaged plasterwork – the firm took moulds of the originals to replicate them exactly – commissioned custom Georgian-style crystal chandeliers and brought in specialists from architectural hardware company Van Cronenburg to restore and recreate 1,100 pieces of 18th-century ironmongery.

But it wasn't all about the period features: a modern kitchen was installed along with an indoor swimming pool – thought to be the biggest in London – a spa, home cinema and more. The end result is a fabulously luxurious home that has all the trappings of a modern billionaire's residence while wholeheartedly respecting the heritage of the historic building. 

One of the many lowlights of Queen Elizabeth II's infamous 'annus horribilis' ('horrible year' in Latin), a devastating fire swept through Windsor Castle in Berkshire on 22 November 1992. Sparked by a faulty spotlight in Queen Victoria's Private Chapel, the blaze destroyed a total of 115 rooms, including nine State Rooms, before it was extinguished by firefighters, who discharged 1.5 million gallons of water to quell the flames.

The damage to one of the Queen's favourite residences was extensive as you can see from this photo of the medieval St. George's Hall taken not long after the blaze. Astonishingly however, only two works of art were destroyed in the fire: a painting of Sir William Beechey and a rosewood sideboard. Heroic staff had managed to save the vast majority of the castle's treasures, which were carried out before the inferno had really taken hold.

The royal family wasted no time restoring the damaged castle. Regarded as the greatest historic renovation conducted in the UK during the 20th century, the restoration arguably improved some of the rooms. St. George's Hall for instance was recreated to a design more in keeping with its original 14th-century appearance.

Controversy surrounded who would actually cover the cost of the renovation, so it was decided the Queen would pay 70% of the final bill by opening Buckingham Palace to the general public for the first time in its long history to raise the funds. This photo shows the Grand Reception Room shortly after the flames had died down. Like St. George's Hall, it too was virtually gutted in the catastrophic blaze. 

The Grand Reception Room is seen here post-renovation with its sumptuous gilded decoration impeccably recreated. All in all, the restoration of Windsor Castle, which took five years to finish, set back the Queen more than $33 million (£26m) with UK taxpayers covering the remaining $14 million (£11m).

Entrepreneur and philanthropist John Caudwell pulled out all the stops with his phenomenal renovation of the Grade II-listed Ancaster House and adjacent 8 Chesterfield Gardens in London's upmarket Mayfair district. The British tycoon, who joined the billionaire club in 2006 after selling his Phones 4U chain for almost $2 billion (£1.5bn), sank a reported $85 million (£65m) into the opulent refurb.

After purchasing the pair of manses in 2012 for $115 million (£87m), Caudwell combined the two properties to create the palatial Mayfair House. Now the UK's most valuable private home, it is worth some $330 million (£250m). The rags-to-riches mobile phone mogul showed off the sensational project in a recent Channel 4 documentary, Britain’s Most Expensive Home: Building for a Billionaire.

Superlatives abound in the ridiculously luxurious mega mansion. Spanning 43,000 feet, the eight-storey, 15-bedroom home is more than twice the size of the Royal Albert Hall. The glittering ballroom, which exudes regal grandeur, is the largest privately owned space of its kind in London and can comfortably fit 120 people.

And there's another surprise in the billionaire's basement... The subterranean swimming pool features a 'volcano' wall and ceiling complete with a realistic lava effect, and there's also a gym, spa, home cinema, library and Art Deco-inspired elevator in the unparalleled property. Caudwell, who has vowed to give away 70% of his fortune to good causes, isn't planning to live in the megamansion. Mayfair House will instead be used to hold events for his charity, Caudwell Children.

Like Mayfair House, Wentworth Woodhouse in South Yorkshire is big on superlatives. Built between 1724 and 1750 by the Marquesses of Rockingham, the sprawling Grade I-listed stately home hides many secrets; it has five miles of corridors, a room for every day of the year and the longest façade of any country house in Europe.

The country house was sold in 1988 to a local businessman and subsequently bought by London architect Clifford Newbold. While both owners carried out renovation work, they failed to restore the property to its former glory. The stately home was eventually acquired in 2017 for $9.2 million (£7m) by the Wentworth Woodhouse Preservation Trust, which is seeking to fully revive the landmark estate. Shown here is the remarkable Marble Saloon, once regarded as the finest Georgian room in England.

The trust most definitely has its work cut out. Its chief executive Sarah McLeod has estimated the final cost of restoring the country house could be as high as $263 million (£200m). Preliminary work fixing the leaking roof has cost $9.5 million (£7.2m) alone. This particular project has been funded by the UK government. 

While Wentworth Woodhouse has a longer façade, London's Buckingham Palace beats it in many other respects. The iconic royal palace and official London residence of Queen Elizabeth II boasts 775 rooms, 760 windows and 1,514 doors, as well as the largest garden in the capital. Unsurprisingly, any extensive renovation of a property this size was always going to cost a fortune.

In fact, the restoration of the building or 'reservicing' as the Palace calls it is expected to cost more than $485 million (£369m) with UK taxpayers footing the bill through the Sovereign Grant. The project is focussed on the 200-room East Wing, which hasn't been refurbished since the Second World War, while its outdated electrics, heating and plumbing date from the 1950s.

The obsolete, inefficient and frankly dangerous electrics, heating and plumbing are being replaced by modern eco-friendly alternatives, which should reduce the palace's carbon footprint by 40% and slash utility bills by £4.5m (£3.4m) per year. Other advantages of the Buck Palace renovation project include longer summer opening hours and additional private tours.

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