Last year, Dutch practice <a href="index.php?page=&url=http%3A%2F%2Fopaworks.com%2F" target="_blank" target="_blank">OPA</a> designed a home wedged in a mountaintop that became a viral hit.
Last year, Dutch practice OPA designed a home wedged in a mountaintop that became a viral hit.
Courtesy OPA
In the wake of the media interest, a client who wanted to make the concept a reality came forward.
In the wake of the media interest, a client who wanted to make the concept a reality came forward.
Courtesy OPA
The home will be built 1,600 meters (5249 feet) above sea level on a cliff in Lebanon.
The home will be built 1,600 meters (5249 feet) above sea level on a cliff in Lebanon.
Courtesy OPA
It will be topped by an infinity pool that doubles as a skylight.
It will be topped by an infinity pool that doubles as a skylight.
Courtesy OPA
Living life inside a mountain
CNN  — 

A madcap proposal for a concrete house inside a cliff went viral last year – and now it’s set to be built, thanks to the internet.

Dutch practice OPA designed a home wedged in a mountaintop, topped by an infinity pool that doubles as a skylight for the underground lair.

In the wake of the media interest, a client who wanted to make the concept a reality came forward and the project will now be realized 1,600 meters (5249 feet) above sea level on a cliff in Lebanon.

Unlike OPA's house in a cliff, many of the most interesting designs in architecture have never been realized. Here's a look at the greatest buildings that never <a href="index.php?page=&url=http%3A%2F%2Fwww.cnn.com%2F2016%2F04%2F12%2Farchitecture%2Fincredible-architecture-that-was-never-built%2Findex.html" target="_blank">were</a>. <br /><br />How different Chicago's skyline would have looked if Calatrava's 2005 design had been built. One thousand four hundred and fifty eight feet (444 meters) of slender twisted steel and glass, the Chicago Spire would have knocked the Willis Tower (formely the Sears Tower) down a peg, trumping it by a whole two meters and a whole lot of style. The 920,000 square foot structure would have featured residential apartments, retail space and a five-star hotel, with each floor rotating 2 degrees around a central core, turning 270 degrees through the height of the building. <br /><br />But then the global financial crisis hit. Construction halted in 2008 with claims that heavy debts had been racked up. In this instance Donald Trump was right: the Chicago Spire had been "<a href="index.php?page=&url=http%3A%2F%2Fwww.chicagotribune.com%2Fbusiness%2Fchi-chicago-spire-biz-20150313-story.html" target="_blank" target="_blank">financial suicide</a>."
The Chicago Spire, Santiago Calatrava —
Unlike OPA's house in a cliff, many of the most interesting designs in architecture have never been realized. Here's a look at the greatest buildings that never were.

How different Chicago's skyline would have looked if Calatrava's 2005 design had been built. One thousand four hundred and fifty eight feet (444 meters) of slender twisted steel and glass, the Chicago Spire would have knocked the Willis Tower (formely the Sears Tower) down a peg, trumping it by a whole two meters and a whole lot of style. The 920,000 square foot structure would have featured residential apartments, retail space and a five-star hotel, with each floor rotating 2 degrees around a central core, turning 270 degrees through the height of the building.

But then the global financial crisis hit. Construction halted in 2008 with claims that heavy debts had been racked up. In this instance Donald Trump was right: the Chicago Spire had been "financial suicide."
courtesy Santiago Calatrava
A two mile-wide geodesic dome over Midtown Manhattan doesn't sound like the most practical way to reduce air pollution and regulate weather, but Buckminster Fuller and Sandao once went to great lengths mapping out plans for one in 1960. Spanning the East River to the Hudson and covering 62nd Street to 22nd Street, they planned for it to be built from shatterproof glass, mist-plated with aluminum to reduce glare from the sun. Weighing 4,000 tonnes, Fuller argued that the structure, built by a fleet of helicopters fitting each glass plate, would cost $200 million and be invisible to the naked eye for those inside. There were potential problems for the dome, however: Fuller stipulated that cars or engines of any kind were to be banned. Oh, and there was the chance the dome might float away. It's been argued that, because the dome's weight was comparable to that of the air beneath it, it could<a href="index.php?page=&url=http%3A%2F%2Fwww.nous.org.uk%2FManhattan.html" target="_blank" target="_blank"> float in hot weather</a>, and would have to be anchored in place with cables. Surprisingly, the idea never took off.
Manhattan Dome, R. Buckminster Fuller and Shoji Sandao —
A two mile-wide geodesic dome over Midtown Manhattan doesn't sound like the most practical way to reduce air pollution and regulate weather, but Buckminster Fuller and Sandao once went to great lengths mapping out plans for one in 1960. Spanning the East River to the Hudson and covering 62nd Street to 22nd Street, they planned for it to be built from shatterproof glass, mist-plated with aluminum to reduce glare from the sun. Weighing 4,000 tonnes, Fuller argued that the structure, built by a fleet of helicopters fitting each glass plate, would cost $200 million and be invisible to the naked eye for those inside. There were potential problems for the dome, however: Fuller stipulated that cars or engines of any kind were to be banned. Oh, and there was the chance the dome might float away. It's been argued that, because the dome's weight was comparable to that of the air beneath it, it could float in hot weather, and would have to be anchored in place with cables. Surprisingly, the idea never took off.
The Estate of R. Buckminster Fuller
Spheres were integral to the work of mathematician Sir Isaac Newton, in life and, at one time, in death. The great scientist worked out the force holding us to the big sphere beneath our feet, and French architect Etienne-Louis Boullee thought it would be a fitting shape to remember him by. <br /><br />In 1784 he drew up plans for a grand, 500 foot (150 m) cenotaph -- eight meters taller than Strasbourg Cathedral, the highest building at the time. Inside was to be a void, with small holes in the building's shell allowing sunlight to pierce through, mapping out star constellations and planets and acting as a vast planetarium. Though never built, etchings of the concept were popular, with copies currently held a the Bibliotheque Nationale de France.
Cenotaph to Newton, Etienne-Louis Boullee —
Spheres were integral to the work of mathematician Sir Isaac Newton, in life and, at one time, in death. The great scientist worked out the force holding us to the big sphere beneath our feet, and French architect Etienne-Louis Boullee thought it would be a fitting shape to remember him by.

In 1784 he drew up plans for a grand, 500 foot (150 m) cenotaph -- eight meters taller than Strasbourg Cathedral, the highest building at the time. Inside was to be a void, with small holes in the building's shell allowing sunlight to pierce through, mapping out star constellations and planets and acting as a vast planetarium. Though never built, etchings of the concept were popular, with copies currently held a the Bibliotheque Nationale de France.
courtesy Bibliothèque nationale de France
Boris Iofan's colossal design for the Palace of the Soviets has become one of the finest examples of an architectural moonshot that fell to earth. The imposing design was the winning entry of an international competition in 1931 for a new administrative and congress hall in Moscow, Russia. At a height of 1,365 feet (416m), it would have eclipsed the Empire State Building as the tallest in the world, while the 160 meter wide, 100 meter tall main hall held the capacity for 21,000 seats. <br /><br />The design was heavily revised over time -- partially under the instruction of Stalin himself -- emphasizing both neoclassical motifs and the gigantic statue of Lenin atop. The foundations were laid down by 1939 but the Nazi invasion in 1941 halted construction. It never resumed, although the abandoned site would still become home to a record-breaking build -- the Moskova Pool, in 1958, the world's largest outdoor swimming pool.
Palace of the Soviets, Boris Iofan —
Boris Iofan's colossal design for the Palace of the Soviets has become one of the finest examples of an architectural moonshot that fell to earth. The imposing design was the winning entry of an international competition in 1931 for a new administrative and congress hall in Moscow, Russia. At a height of 1,365 feet (416m), it would have eclipsed the Empire State Building as the tallest in the world, while the 160 meter wide, 100 meter tall main hall held the capacity for 21,000 seats.

The design was heavily revised over time -- partially under the instruction of Stalin himself -- emphasizing both neoclassical motifs and the gigantic statue of Lenin atop. The foundations were laid down by 1939 but the Nazi invasion in 1941 halted construction. It never resumed, although the abandoned site would still become home to a record-breaking build -- the Moskova Pool, in 1958, the world's largest outdoor swimming pool.
courtesy Tchoban Foundation
Zaha Hadid's Tokyo Olympic Stadium was many things -- ultramodern, typically curvacious and above all, very expensive. The design for the 2020 Games was also intended for the 2019 Rugby World Cup, but it was not without its detractors: leading Japanese architect Arata Isozaki labeled it a "disgrace to future generations." However construction costs spiraled as the price of steel rose, with a stadium's new price tag increasing to 250 billion yen ($2.02 billion). Eventually in July 2015 Prime Minister Shinzo Abe announced the design was being scrapped for a more cost-effective alternative.
Tokyo Olympic Stadium, Zaha Hadid —
Zaha Hadid's Tokyo Olympic Stadium was many things -- ultramodern, typically curvacious and above all, very expensive. The design for the 2020 Games was also intended for the 2019 Rugby World Cup, but it was not without its detractors: leading Japanese architect Arata Isozaki labeled it a "disgrace to future generations." However construction costs spiraled as the price of steel rose, with a stadium's new price tag increasing to 250 billion yen ($2.02 billion). Eventually in July 2015 Prime Minister Shinzo Abe announced the design was being scrapped for a more cost-effective alternative.
Courtesy Zaha Hadid Architects
The Coney Island Globe Tower, seen at the rear of this New York Tribune cover, was the ambitious megastructure dreamed up by Samuel Friede. Proposed in May 1906, it was to include a 700 foot (213 meter) sphere with multiple floors, containing everything from restaurants to garden to a bowling alley -- not to mention the world's largest ballroom and a theme park. All in all, it would have fitted 50,000 people and operate 24 hours a day.<br /><br />As with most grand schemes, the problem was money. Friede advertized the project looking for $1,500,000 of investment, saying the project was expected to pay 100% interest annually. The cornerstone was laid on May 26, and investors jumped at the chance to make such returns. All was not how it seemed, however. <br /><br />Delays followed and anxiety spread throughout the city. Another ceremony was held when the first piece of steel was moved into place. Promises were broken and the threat of injunctions followed. By 1908 it was discovered that the ambitious project wasn't just a pipe dream -- it was a fraud.
The Coney Island Globe Tower, Samuel Friede —
The Coney Island Globe Tower, seen at the rear of this New York Tribune cover, was the ambitious megastructure dreamed up by Samuel Friede. Proposed in May 1906, it was to include a 700 foot (213 meter) sphere with multiple floors, containing everything from restaurants to garden to a bowling alley -- not to mention the world's largest ballroom and a theme park. All in all, it would have fitted 50,000 people and operate 24 hours a day.

As with most grand schemes, the problem was money. Friede advertized the project looking for $1,500,000 of investment, saying the project was expected to pay 100% interest annually. The cornerstone was laid on May 26, and investors jumped at the chance to make such returns. All was not how it seemed, however.

Delays followed and anxiety spread throughout the city. Another ceremony was held when the first piece of steel was moved into place. Promises were broken and the threat of injunctions followed. By 1908 it was discovered that the ambitious project wasn't just a pipe dream -- it was a fraud.
The Library of Congress
It was supposed to be the centerpiece of Liverpool, England's redevelopment as European Capital of Culture in 2008. As it stands, all that remains of the Fourth Grace (also known as The Cloud) are these beautiful renderings. The concept, which was once described as a "diamond knuckleduster" by <a href="index.php?page=&url=http%3A%2F%2Fwww.theguardian.com%2Fuk%2F2004%2Fjul%2F23%2Fnortherner.helencarter" target="_blank" target="_blank">The Guardian</a>, won an architectural competition in 2002 for a fourth building to sit alongside Liverpool's Three Graces - the Royal Liver Building, the Cunard Building and the Port of Liverpool building. A mixture of museum and commercial rental space, its £228 million ($322 million) budget spiraled to £324 million ($457 million) by 2004, spelling the end to a design that the locals, if not the architectural community, were set against from the off.
Fourth Grace, Will Alsop —
It was supposed to be the centerpiece of Liverpool, England's redevelopment as European Capital of Culture in 2008. As it stands, all that remains of the Fourth Grace (also known as The Cloud) are these beautiful renderings. The concept, which was once described as a "diamond knuckleduster" by The Guardian, won an architectural competition in 2002 for a fourth building to sit alongside Liverpool's Three Graces - the Royal Liver Building, the Cunard Building and the Port of Liverpool building. A mixture of museum and commercial rental space, its £228 million ($322 million) budget spiraled to £324 million ($457 million) by 2004, spelling the end to a design that the locals, if not the architectural community, were set against from the off.
Virtual Artworks/All Design
Another victim of the global economic slump, the Nakheel Harbour and Tower in Dubai failed to fly when, six years after being proposed, it was canceled in December 2009. The 3,280 feet (one kilometer) high tower was first mooted as the centerpiece of Palm Jumeirah, the vast man-made archipelago in the Persian Gulf, although it was later re-located closer to the Dubai Marina. The design for the mixed-use complex drew on Islamic monuments of the past according to the architects, invoking the Harbor of Alexandria, the bridges of Isafahan, the gardens of Alhambra and the promenade of Tangier -- but like the Lighthouse of Alexandria, the plan, estimated to cost $38 billion, came crumbling down.
Nakheel Harbour and Tower, Woods Bagot —
Another victim of the global economic slump, the Nakheel Harbour and Tower in Dubai failed to fly when, six years after being proposed, it was canceled in December 2009. The 3,280 feet (one kilometer) high tower was first mooted as the centerpiece of Palm Jumeirah, the vast man-made archipelago in the Persian Gulf, although it was later re-located closer to the Dubai Marina. The design for the mixed-use complex drew on Islamic monuments of the past according to the architects, invoking the Harbor of Alexandria, the bridges of Isafahan, the gardens of Alhambra and the promenade of Tangier -- but like the Lighthouse of Alexandria, the plan, estimated to cost $38 billion, came crumbling down.
courtesy Woods Bagot
Here's what world famous skylines could have looked like

Channeling his inner Kim Kardashian, OPA co-founder Laertis-Antonios Ando Vassilou told ArchDaily the plan was to “break the internet.”

30 stunning feats of design battle to be the world's best building

“We wanted to create a sensation in every possible way and through this project to actually showcase our platform this project describes fully our aesthetics and design philosophy,” he added.

Read: A bridge too far? 11 spectacular new bridges that break the mold

Ando Vassilou also recommended other emerging architects do the same by promoting their projects online.

“By chasing the viral idea at least you sharpen your skills and strengthen your portfolio with interesting projects,” he said.

Check out The Spaces for more innovative architecture projects from around the world.