While they might be beloved today, some of the world's most iconic landmarks and buildings haven't always been quite so popular.

From The Shard to the Eiffel Tower, read on to discover the stories behind the architectural "white elephants" that once looked as though they were heading for disaster – but ultimately managed to prove the critics wrong. All dollar amounts in US dollars.

Architecturally speaking, the Leaning Tower of Pisa was a disaster from day one. The soft ground it was built on left it teetering dangerously close to collapse almost as soon as construction began, way back in the 12th century.

Fast-forward almost 800 years and the Italian dictator Benito Mussolini was so mortified by the tilt – which he considered to be a source of national embarrassment – that he tried and failed to straighten it out.

Far from being a national embarrassment, however, the distinctive lean is now what draws in the tourists. Around five million people visit the Leaning Tower of Pisa every single year, with some Pisans so proud of their famous landmark that they even oppose efforts to stop the structure from tilting over even further.

This monument to George Washington (1732-1799), which can be found in the US city that took his name, stood half-finished for more than two decades.

Described by writer Mark Twain as looking like a "factory chimney with the top broken off", the obelisk wasn't exactly a fitting tribute to one of America’s Founding Fathers. Construction first began on the project in 1848; it's pictured left in around 1860.

Proposals for the monument were first drafted as early as the 1780s. However, the project took decades to reach completion, and the Washington Monument wasn't opened to the public until 1888 – a whole century after the initial idea.

Political rows, a lack of funding, the death of an architect, and the outbreak of the American Civil War all slowed down its progress. But despite its rocky start, the Washington Monument became a hit with tourists and is still popular to this day, attracting hundreds of thousands of visitors a year. 

It's hard to believe that the Brooklyn Bridge, which connects Brooklyn to Manhattan and has become an iconic part of the New York City skyline, was ever contentious. But when work on the bridge – which measures in at 6,016ft (1,833.7m) long – first began in 1870, it was plagued with problems.

The project was faced with considerable opposition from the shipping industry, which believed the bridge was too short for ships to pass underneath it. In addition, several workers were tragically killed during its construction, including John Augustus Roebling, the engineer who designed the bridge. He befell a freak accident: in 1869, while working out the precise location of where the bridge would stand, his foot was crushed by a ferry and he died a few weeks later.

From skyrocketing costs to continuous opposition, construction of the Brooklyn Bridge was no easy feat. But when it finally opened to the public on 24 May 1883, opinion quickly changed.

According to contemporary newspaper reports, toll operators on the bridge were processing 100 people every minute within a week of the opening ceremony. Fast-forward to the 21st century and it's estimated that around 4,000 pedestrians walk across it every day. 

The Eiffel Tower, which opened to the public in 1889, sparked uproar in French high society before its construction had even been completed.

The writer Guy de Maupassant called it a "giant ungainly skeleton". In a letter of protest, he and other luminaries of the arts world, including Charles Garnier, Charles Gounod, and François Coppée, fumed that its shadow would loom "like a dark inkstain" over Paris for decades to come.

These well-heeled critics’ views turned out to be miles away from the eventual public opinion on Gustave Eiffel’s 300m-high structure. Just a few weeks after its completion, two million people came to marvel at it when Paris hosted the World’s Fair and it has been a hugely popular French landmark ever since. It currently attracts somewhere between six to seven million visitors every year. 

At 1,250ft (381m) tall, this iconic landmark was the world’s tallest building when it opened in 1931. But this wasn't quite enough to attract tenants in the middle of the Great Depression, and the Empire State Building stood mostly empty until 1933.

In fact, due to the impact of the economic slump and World War II, the so-called "Empty State Building" failed to turn a profit until the early 1950s, according to the New York Times.

Even in the early 2000s, it "could not compete with the sleek new towers" when it came to attracting New York firms, the Wall Street Journal reported. But the building's saving grace is, arguably, its ticketed observation decks, which offer stunning views of the city and attract around four million visitors every year.

Depending on which of the three decks you choose to visit, the cost of a standard adult ticket currently ranges from $44 (£33.45) to $77 ($58.54; prices correct as of March 2022). 

Architect Frank Lloyd Wright’s quirky structural design for the Guggenheim Museum was so controversial that even avant-garde artists lined up to oppose it.

The initial proposals reportedly breached no fewer than 32 building regulations and the structure took around 16 years to complete. By that point, Wright had sadly passed away, as had Solomon Guggenheim, the wealthy businessman and art collector who established the museum in the first place.

Yet when the museum finally opened in 1959, the world quickly fell in love with the building that the author Norman Mailer had once said "shattered the mood of the neighborhood".

Today, the Guggenheim is one of New York's most popular museums, with more than one million visitors every year. 

The Sydney Opera House once looked set to go down in history as one of Australia’s biggest architectural failures. Danish architect Jørn Utzon (pictured) won an international competition to design the building in 1957 but resigned from the project nine years later following heavy government criticism.

The construction was supposed to cost around AUS$7 million ($5m/£3.8m) and be finished in 1963. By the time the Opera House was finally completed in 1973, its cost had ballooned to a staggering AUS$102 million ($74m/£56.6m). 

However, the Sydney Opera House quickly became an iconic global venue, and over the years has hosted everyone from Pope John Paul II to Nelson Mandela, as well as thousands of performers and artists. It was also the setting for some of the events at the 2000 Summer Olympics.

In 1999, Utzon was welcomed back into the fold and made a design consultant for future work on the landmark. In 2007, he became only the second person in history to see one of their designs become a UNESCO World Heritage Site. 

None other than the French president Georges Pompidou commissioned and signed off the eyebrow-raising design of the Pompidou Centre, which opened in 1977. 

Its inside-out design was like nothing the city – and perhaps even the world – had ever seen before, with its escalators, electricity cables, and structural support all boldly exposed.

The now-landmark was built in the face of significant local opposition, with early critics describing it as looking like an "oil refinery".

Despite early doubts, however, the French public have embraced the cultural hub, a response which National Geographic described as "love at second sight". It's also a huge hit with tourists, and currently houses the Public Information Library, the Musée National d'Art Moderne, and the Institute for Research and Coordination in Acoustics/Music (IRCAM).

In fact, it has almost been too successful. The Pompidou Centre was reportedly built to accommodate around 8,000 visitors a day but attracted five times as many in its first 20 years. From 2023, the site will be closed for around four years to allow vital restoration work to take place. 

Building a 71ft (21.6m) metal and glass pyramid outside a former royal palace in the centre of Paris was always going to be controversial.

However, even I. M. Pei, the architect behind the design, was surprised by how furious and long-lasting the opposition to his work would be.

The pyramid was slammed not only as an eyesore that sat in contradiction to the French Renaissance architecture of the Louvre Palace, but also as being little more than a "vanity project" by the new socialist President Francois Mitterrand.

Since its completion in 1988, however, the extension has become a prized national site. Pei used crystal-clear glass and reportedly limited the pyramid’s height to complement, rather than overshadow, the surrounding buildings.

Within a few weeks of its launch at the start of 2000, this £789 million ($1bn) London landmark seemed doomed to become Britain's ultimate white elephant.

According to The Independent, operators were already struggling to pay their bills, construction costs had spiralled over budget, and the millennium-themed exhibitions were failing to attract enough visitors. 

There was huge uncertainty over the dome’s future until new owners AEG transformed it into an entertainment venue in 2002. The building was considered so unprofitable that the government gave it away for free in exchange for a cut of the future profits.

The site was renamed The O2 Arena after a multi-million-pound sponsorship deal was signed with the UK phone company, and it reopened its doors in 2007. 

The O2 was promptly crowned the world's most popular entertainment venue in 2008 and 2009, and is currently the world's most active music arena in terms of ticket sales. It has hosted concerts by acts ranging from Iron Maiden and the Rolling Stones to Britney Spears and Katy Perry, and was also used as a venue during the 2012 Summer Olympics.

Designed by the Spanish architect Enric Miralles, the Scottish Parliament Building in Edinburgh was eventually completed in 2004 – three years behind schedule and at least 10 times over its initial budget.

The building's unusual design proved unpopular with locals, many of whom believed the skyrocketing cost was a poor use of public funds. Even worse, it's tipped to need extensive refurbishment by 2060 due to "in-built problems" according to Peter Wilson, who is the former project architect for the Museum of Scotland.

But despite a public inquiry into the mismanagement of the building's construction, general opinion seems to have softened since 2004.

In 2005, the Scottish Parliament Building won the prestigious Stirling Prize, an accolade from the Royal Institute of British Architects that celebrates architectural brilliance.

And even Peter Wilson had something almost positive to say about the structure, noting: "You could say the building has more value than some of the occupants. If you replaced them with wall or loft installation, you wouldn't know the difference".

When the 31.35-mile (50.46km) Channel Tunnel was unveiled in 1994, Queen Elizabeth described it as one of the world's "great technological achievements".

But it wasn't all plain sailing. The company behind the megaproject, Eurotunnel (now called Getlink), had racked up enormous debts and spent almost double its original budget to complete the tunnel on time. Many people were sceptical of its long-term profitability, not least because it was still making a net loss over 10 years later. 

To get out of the red, Eurotunnel underwent a financial restructuring in 2007, reducing its shareholder stake and writing off millions of pounds in debt.

A decade later, the tunnel was carrying over 20 million passengers every year and it currently accounts for around 60% of the cross-Channel traffic. 

The Chinese Central Television HQ (CCTV HQ) in Beijing, China, has had a troubled history. When the construction project was first announced in 2002, many believed that it was too ambitious to be built.

Western media accused Dutch architect Rem Koolhas of enabling state propaganda; Chinese media accused him of basing his design on a naked woman on her knees.

Construction was not finished in time for Beijing's 2008 Summer Olympics, and a tragic fire in February 2009 left the building's future even further in the balance. But the Chinese government pressed on and it has persevered to become an iconic part of Beijing’s skyline.

In 2013, CCTV HQ won an award for being the world’s best tall building and the Wall Street Journal has described it as "a symbol of the capital’s transformation into a modern metropolis".

Boris Johnson, who was the then-Mayor of London, described The Shard as "a most amazing place" when he officially opened it in 2013. At the time, it was the highest building in western Europe.

But a year later, it was dubbed "the tallest white elephant in the world" by the Daily Mail, which noted that not a single office in the building had been let, leaving The Shard close to empty. 

Designed by Italian architect Renzo Piano, the 1,016ft (310m) tower was initially written off by many, with people believing that its location south of the River Thames and unusually-shaped offices condemned it to failure. But the building's owners, which include the Qatari government, may have had the last laugh.

In October 2017, it was announced that The Shard's offices were "virtually full", with tenants including TV station Al Jazeera, jewellers Tiffany & Co., and food retailer Kraft Heinz. The View from The Shard, a tourist attraction, has also raked in countless visitors. 

Now discover the megaprojects that spiralled out of control.