It's hard to imagine this planet without its biggest landmarks, from Sydney Opera House to the Statue of Liberty. But, of course, there was a time when they existed only as plans or blueprints, or in the mind's eye of the world's greatest architects. So, how did they become the attractions they are today?

Read on as we share incredible images and stories of the world's top attractions as they were built...

Today, in the Black Hills of South Dakota, four of America’s most formative presidents look out from a rugged cliff face. It was state historian Doane Robinson who first had the idea for a mammoth national monument in the region, but its eventual design was the brainchild of sculptor Gutzon Borglum. Borglum is pictured here in his local studio with an early model of the landmark.

It took around 14 years to build the four, gigantic presidential faces, with work beginning in 1927 and finishing in 1941. Great chunks of rock were blasted away with explosives, then the striking likenesses were carved out with chisels and jackhammers. This photo was taken circa 1940, towards the end of construction: you can clearly see the sage profiles of Thomas Jefferson and George Washington a little farther away. However the site is controversial. The Black Hills is sacred ground for Indigenous people and this area was taken from them by the government after a series of bloody battles.

It took 18,038 metallic parts and some 50 engineers and designers to realise the Eiffel Tower, the great symbol of France that stands proud in Paris. Designed by civil engineer Gustave Eiffel, it was first dreamt up for the World’s Fair of 1889, with building work commencing in 1887. You can see the tower beginning to take shape in this photo of the first platform from 1888 – wooden scaffolding (visible here) and small steam cranes were used in its construction.

This photo was taken about four months shy of the tower’s completion and, by this point, the naysayers who doubted the soundness of Eiffel’s bold design had been silenced – though many in the art world still saw it as an eyesore. The individual elements were constructed in Eiffel’s own factory in a Parisian suburb, and up to 300 workers came together to assemble the colossal structure.

Upon its completion, the giant latticed tower was more than 984 feet (300m) tall and had taken just 26 months to build. Also a source of fascination was the tower’s hydraulic elevator system (seen here under construction), which was a spectacular feat of engineering for the time. Today two historic lifts remain in operation at the tower.

Love this? Follow our Facebook page for more travel inspiration

Dominating Trafalgar Square in central London, Nelson’s Column is dedicated to Vice-Admiral Horatio Nelson, who led Britain to major victories during the Napoleonic Wars. The design for the monument, the vision of English architect William Railton, was decided in a competition, and it took three years to realise. This photo dates to 1843 and depicts the unfinished base of the landmark and a short section of its shaft – the platform would later be decorated with bronze reliefs.

Canada’s Parliament building has had a tumultuous history, beginning right back in the 1850s, when Ottawa was first selected as the capital. Work on the Gothic Revival-style buildings on Parliament Hill began in 1859 and was eventually completed in 1866. The sprawling Centre Block is pictured here under construction in 1863.

However, the buildings were ravaged by a fire in early 1916. The Library of Parliament was spared, but the rest of the site, including the Centre Block pictured previously, was gutted by flames. Canada was quick to begin work again, though, and by the end of the year, reconstruction had commenced. This 1916 photograph shows the beginnings of that construction work, with the striking, cupola-topped Library building rising from the foundations. 

These are the earliest ever photos of Canada

Fast-forward one year and work continues. This 1917 photo shows Parliament’s Centre Block once again taking shape, with the pointed library building peeking out from behind it. The building work, which also included the soaring Peace Tower, was finally finished in 1927.

The most famous of the Big Apple’s bridges, Brooklyn Bridge is lauded for its bold design and ingenuity – but this architectural masterpiece came at a cost. At least 20 men died during its construction, including the bridge’s designer, John A. Roebling, whose foot was crushed in an accident during a site inspection. He died of tetanus three weeks later. The bridge is beginning to take shape in this 1870s shot.

Other workers died from falls or injuries and many suffered from decompression sickness or “the bends” – a result of pressurised air in the caissons the men worked in. Upon the landmark's completion in 1883, it was the longest suspension bridge in the world, spanning around 1,600 feet (488m) from tower to tower. But even when the structure was finished, there were still fears over its safety. Circus owner P. T. Barnum famously led 21 elephants over the bridge in 1884 to allay the public’s anxieties. It’s seen here around a decade earlier, as cables were put into place in 1875.

Probably Australia’s most iconic building, the Sydney Opera House has defined Sydney Harbour since the 1970s, its roof appearing like a series of sails in the wind. The design of the photogenic landmark was decided in a competition that ran in the 1950s – Danish architect Jørn Utzon won over judges with his unique proposal. This photograph was taken in 1963 and you can clearly make out the shape of the building’s distinctive roof as it’s constructed.

The construction of this famed Aussie landmark was not all smooth sailing though. The Opera House was originally supposed to open its doors in the early 1960s, but difficulties realising the complicated design led to time delays and bursting budgets. Utzon eventually resigned from the project, which would not be completed until 1973. Now it’s one of Sydney’s greatest monuments, but here it is again, in 1963, in the midst of the construction woes and controversy.

Another beloved landmark Down Under, Sydney Harbour Bridge came earlier than the famous opera house and was finished and opened in 1932. The idea for a bridge that would connect the centre of Sydney to its northern suburbs had been floated in the 1910s by civil engineer John Bradfield, but the First World War prevented work from getting underway. By 1922, though, attention had turned back to the project and construction soon began. This photo shows the progress made by 1926. 

These are Australia's most dangerous tourist attractions

The bridge was to be an intricate steel structure, with its great arches built out from each bank until they finally met in the middle. It’s pictured here circa 1930, with its mighty arch nearing completion. When finished, the arch spanned a whopping 1,650 feet (503m) and it remains a highlight of the Sydney skyline today.

The idea for the Statue of Liberty – gifted to the USA by the French – was first born in the 1860s, with a view to mark the centennial of the Declaration of Independence in 1876. French sculptor Frederic Auguste Bartholdi was commissioned to design the monument, and he in turn drafted in help from Gustave Eiffel, who assisted with the statue’s structure. Bartholdi is captured in this 1870s shot explaining how Lady Liberty’s hand is constructed from the inside.

Before she made it across the pond, though, Lady Liberty was presented in sections at Paris’ World’s Fair in 1878. This photo shows her gargantuan head propped on a pedestal on display at the event.

The official pedestal was designed and built on American soil by architect Richard Morris Hunt, and finished in 1886. Lady Liberty herself arrived at New York Harbor one year before, in 1885, ready to be assembled on her shiny new plinth. Her face is pictured here in June 1885, as she was unpacked from around 214 crates. She was finally dedicated in October 1886. 

See more vintage images of America's most historic attractions

Though the first wing of the Capitol Building was finished in 1800, the building as we see it today wouldn’t take shape until later. The current, cast-iron dome, designed by American architect Thomas Ustick Walter, replaced an earlier one built by Charles Bulfinch in the 1860s. It rises to 287 feet (87m) and was modelled on that of St Peter’s Basilica in the Vatican City – it’s pictured here in 1861 during its construction.

This fairy-tale castle in Germany’s Bavaria region is known as the inspiration for Cinderella Castle at Disney’s Magic Kingdom – but it began life as an isolated retreat for shy King Ludwig II, who was inspired by the whimsical fortresses of the Middle Ages. Neuschwanstein would take almost two decades to complete, with work commencing at the site in 1868. It’s pictured here in the early 1880s.

Though he had already moved into the castle, King Ludwig II would sadly never see his Romanesque-style vision entirely completed. He died in 1886 having lived in the unfinished palace for just 172 days – it was opened to the public shortly after his death. You can see the construction work still lingering in this photo dated to 1886. 

Check out more of Germany's most beautiful castles

Construction of the Grand Central Terminal that stands today got underway in 1903 and remains an enduring attraction in New York City.  A replacement for an earlier station, it's celebrated for its Beaux Arts-style architecture, and boasts a facade complete with intricate sculptures, columns and an ornate clock face. It's pictured here, in the throes of construction, around 1912 – it would be finished and opened to the public in 1913.

The mighty focal point of the Gateway Arch National Park, this monument has towered over the city of St Louis since the 1960s. The arch was built to commemorate St Louis’ role in the Westward Expansion of the States during the 19th century, when settlers poured into the American west – a movement pioneered by president Thomas Jefferson. In this 1960s snap you can see the stabilising strut that has been put in place as the landmark takes shape.

The monument’s design was decided in a contest in the 1940s, which saw Eero Saarinen’s gigantic 630-foot (192m) arch beat out the competition. It’s captured here in 1965, the same year it was completed.

Today it remains the tallest monument in the United States. We see the arch here in 1965, in its final stages of construction, as the keystone is hauled into place. Legend has it the keystone contains a time capsule containing the signatures of thousands of St Louis residents.

See if you can guess these famous landmarks from their close-ups

Standing proud at the western end of the National Mall, the Lincoln Memorial commemorates America’s 16th president. Work on the foundations began in 1914 and the cornerstone of the monument was first laid in 1915. The mammoth statue of the seated man is pictured here during its installation in 1920, two years before the landmark was dedicated.

One of the world’s most famous and striking cantilever bridges, Forth Bridge first opened back in 1890 to carry rail traffic over the Firth of Forth. The design of engineers Sir John Fowler and Sir Benjamin Baker, it was a momentous feat of engineering when constructed in the 19th century, and it still counts itself among the planet’s longest cantilever bridges. Its intricate form is pictured here coming together in the 1880s.

Some 4,000 workers were employed at the peak of the bridge’s construction, and sadly 57 of them lost their lives during the process. The resulting structure, today a UNESCO World Heritage Site, remains a striking tribute to them. It’s pictured here circa 1888, a couple of years before its completion. 

These are the world's most beautiful bridges

This enormous marble obelisk soars to 555 feet (169m) and was built as a tribute to first president George Washington. Construction of the monument – which was originally intended to comprise a large pantheon as well as an obelisk – began in 1848, but funds soon dwindled. Work halted and wouldn’t begin again until after the Civil War. It recommenced in the 1870s, under the eye of president Ulysses S. Grant, and the landmark was finally dedicated in 1885. It’s seen here, partially completed, in the 1860s.

A more recent architectural achievement, the CN Tower, or Canadian National Tower, was finished in 1975 in Toronto. A masterful feat of construction, it soars to 1,815 feet (553m) and was actually the world’s tallest free-standing structure right up until 2007, when it was overtaken by the Burj Khalifa. You can see it here gaining height in 1973.

Construction of this juggernaut involved more than 1,500 workers and the concrete tower is topped out with a 335-foot (102m) antenna. This 1975 photo shows a Sikorsky CH-54 helicopter moving the giant crane used to build the tower, so the antenna could finally be fitted.

One of the most distinctive shapes along the Big Smoke’s skyline, the London Eye – formally opened at the end of 1999 – was built to mark the new millennium. It’s a striking sight, with six backstay cables holding up the entire structure and a diameter that stretches 394 feet (120m) across. Pictured here in September 1999, the wheel’s enormous bulk lies across the Thames, ready to be lifted into place.

Can you guess these UK landmarks from their close-ups?

Held up as an Art Deco icon, New York’s Empire State Building (antenna excluded) rises to 1,250 feet (381m) and was the tallest building on the planet upon its completion. Beginning in 1930, its construction involved a whopping 3,000 workers – one of them is pictured bolting metal beams in this 1930 shot.

Astonishingly, the Empire State building took just one year and 45 days to build, shooting up at a pace of 4.5 storeys per week, until it was eventually opened in May 1931. It’s captured here in 1930, soaring towards the sky, its stepped lower half already in fine shape.

From one great New York landmark to another: soaring across the East River (and not to be confused with Brooklyn Bridge), this is one of the most striking crossovers in the Big Apple. Work on the suspension bridge began at the turn of the century, and it was opened to traffic in 1909. It’s pictured here during the construction of its main span, which would eventually stretch out to 6,855 feet (2,089m).

Find the most impressive bridge in your state here

Still the tallest building in London, The Shard was completed in 2012, and its uber-modern design was the vision of Italian architect Renzo Piano. It took more than 1,450 workers from 60 countries to build this glass behemoth, which rises to 1,004 feet (306m) and has a steel spire weighing 500 tonnes. It’s pictured here as it takes shape in April 2011.

Building Bristol’s jaw-dropping Clifton Suspension Bridge was no easy feat – in fact, the inscription on the Leigh Woods tower, “Suspensa Vix Via Fit” (“a suspended way made with difficulty”) is a reminder of just what a great task it was. It all began in 1753 with merchant William Vick, who bequeathed funds for a bridge spanning the Avon Gorge upon his death. It’s seen taking shape more than a century later in this 1863 photograph.

Work on the bridge – to a design by civil engineer Isambard Kingdom Brunel – wouldn’t begin until 1831, after Vick’s original bequest had had some time to accumulate. However, the Bristol riots of 1831 soon caused construction to halt and dwindling funds would see that work remained paused for decades. After Brunel died in 1859, the bridge was completed in part as a tribute to the late engineer, with revised designs by William Henry Barlow and Sir John Hawkshaw. It’s captured here under construction in 1864, the same year it was finally finished.

When this mighty “international orange” structure was first built, it was the longest and tallest suspension bridge in the world. Construction of the bridge, which spans the Golden Gate strait, began in 1933 and proved to be a tumultuous exercise. Eleven people met their deaths during the erection of the landmark, which saw workers brave great heights over swirling currents. Courageous workers are pictured here in 1935, standing on a catwalk as they attach cables from the bridge.

Divers also plummeted some 90 feet (27m) below the water’s surface to remove rock for the construction, and a cargo vessel colliding with the access trestle in the early stages delayed the bridge’s completion. When the bridge was finally finished, in 1937, its main span stretched out for 4,200 feet (1,280m) and its towers soared to 746 feet (227m). This striking photo was taken earlier that same year.

Now take a look at these incredible vintage photos of world-famous landmarks