The latest technology made impossible things possible. When it comes to structures built in extreme places, many of the world's most distinctive buildings wouldn't be possible without the use of the most advanced technology.

Architects use various solutions and tools to test every possible scenario and fundamental design before they decide to build a structure. Modern technology is what made modern architecture possible. Because of this architecture, you can now recognize entire cities by their skylines.

The best examples are the tallest building on the planet, Dubai's Burj Khalifa, the Gherkin in London, and the Opera House in Sydney. While these are all the finest examples of most magnificent structures ever built by man, how many people actually took the time and asked themselves how these buildings first came to be?

If it weren't for computer technology like CAD, these structures wouldn't be able to exist in their current form. Modern technology fundamentally changed the way structures are planned, designed, and built.

Digital tools didn't just improve the look of these amazing buildings; they allowed for the construction to take place by providing solutions to the real problems. Let's take a look at five examples of extreme buildings.

1. Opera House - Sydney

This extreme building wouldn't be able to stand up without careful planning and designing. Before it was built, the Opera House gave way too many headaches to local officials, architects, contractors, and everyone else involved.

Due to its amazing and incredibly innovative design at the time, the officials were afraid that the structure wouldn't be able to stand up. It was Jorn Utzon, a Danish architect, who won the design competition.

He brought a different, flamboyant solution - to test the entire project in CAD. This kind of test was the first of its kind, ever. CAD was used to determine if the proposed design was structurally viable.

It took a tremendous amount of time to complete the process. The result is the building we see today. The structure turned out to be narrower and taller than it was originally designed to be, but it's definitely one of the most recognizable structures on the planet.

2. The Gherkin - London

The Gherkin or 30 St Mary Axe in London is next in line with the most extreme buildings. The initial problem with this incredible structure was the wind or its ability to withstand it. Because of its unbelievable size, the structure would be caught in the whirlwinds at its base.

Such whirls would eventually tear down the structure. An entire team of architects worked on solving this problem. They used CAD to develop computer models in different shapes until they finally found the solution - an egg-like shape design that minimized the whirls around its base.

It was its innovative design that resembled some kind of a stretched egg that made the building one of the most distinctive constructions in the world. That aside, many world-leading architects and experts found new inspiration in the way this innovative design solved the problem with air currents.

Led by this example, they started following the same methods, using CAD and other computer model simulations to take care of every aspect of the structure before it enters the final stage.

3. Great Court at the British Museum - London

The Great Court at the British Museum initially started as a plan to make some renovations to parts of the building. It was to become the very first national public museum in the world. Due to its complexity, the project turned out to be much more delicate than it was predicted at first.

The initial design includes turning the entire inner courtyard of the museum into a covered public square, the largest one ever seen in Europe. The square would be enclosed by a steel and glass roof. What's interesting about this initial design was the fact that it put the most popular Reading Room at the center of the museum.

The center and the whole courtyard were sitting there, occupying the space in the British Museum without any purpose. This lost space was successfully repurposed into one of the most iconic structures in modern architecture.

By repurposing the courtyard and putting the center of the museum back into function, the entire building came back to life once more. Despite enormous challenges that designers had to overcome, the Great Court came to life, changing the whole structure for the better and increasing public space by 40%.

The greatest challenge was the canopy. It was built out of 3,312 glass panes, each pane being different from the other. To position these panes properly, designers and architects had to develop a computer program to determine the angles and dimensions of each pane.

4. Burj Khalifa - Dubai

Designing and constructing tall buildings becomes much more difficult when you don't take your arch-enemy into account - the wind. Burj Khalifa is the tallest building in the world, measuring at an incredible 828m (2,717ft). If you feel like taking a swim, this building has the highest swimming pool in the world - on the 76th floor.

With the goal to make the construction of a magnificent piece of architecture happen, designers and architects had to run 40 different tests with wind tunnels, and the only way to make these tests possible was to use CAD. CAD made everything possible, and designers were free to conduct experiments on all possible situations and scenarios.

The biggest interest was to discover the effects that wind might have on the structure, its tower, and its occupants. Massive facade pressure and structural integrity were done, including various analysis models. The tests discovered that the building was only possible if rotated by 120 degrees.

The rotation would help to reduce all the impacts from natural habitat, including the stress caused by the winds. At such a height, the wind tends to be a considerable problem, endangering the entire structure and its integrity.

5. City Hall - London

There are many amazing buildings in the world. Still, City Hall in London deserves to be on this list due to bringing considerable innovations in the way architects and designers plan and design their structures. First of all, the aesthetic value of this building alone is worthy of admiration.

City Hall in London became famous because of many things, but one of the most distinctive features is the helical staircase. The staircase is as tall as the building is high, measuring 500m (1,640ft). The stairs were shaped specifically to solve an acoustic challenge.

Since the City Hall is very large, the sound bounced around, making considerable noise. To break it up, the architects had to team up with sound specialists and design the stairs that would help reduce the noise by reducing echoes and trapping sound behind them.

And again, all of this wouldn't be possible if it wasn't for CAD. Digital technologies not only transformed architecture, but they made the construction of these extreme buildings possible.