Exploring the buildings that never were

Every great building starts as an idea—a sketch, a vision, a plan - but not every project makes it to completion. Around the world, some of the most imaginative, ambitious and occasionally bizarre construction wonders have been lost to history. These unbuilt marvels might have redefined cityscapes. Instead, these "forgotten" structures offer fascinating lessons for the modern construction industry.

Before looking at specific examples, it's useful to understand why some buildings are simply left – unbuilt – for want of a better term. While each story is unique, some common reasons do emerge such as economic downturns, technological limitations, political changes, environmental concerns – and even public backlash. So, let’s take a look at some of those famous unbuilt projects – which never quite made it off the ground – and a few more that could face the same fate in a few years time..

1. Tatlin's Tower (Russia, 1919)

One of the most ambitious, unbuilt architectural projects is the 1919 Monument to the Third International by Russian artist Vladimir Tatlin. Known as Tatlin's Tower, it was designed to stand at over 400 metres and rotate. Planned as a symbol of revolutionary Russia, Tatlin’s design involved two main structures spiralling together, representing unity and motion. However, the project faced overwhelming technical and financial challenges - largely due to the limits of engineering in the early 20th century.

2. The Illinois (USA, 1956)

Architect Frank Lloyd Wright proposed a visionary mile-high skyscraper called "The Illinois" in 1956. With over 500 floors, it would have dwarfed the Empire State Building. However, the construction challenges, particularly the materials and elevators (lifts) required, made it impractical. Modern skyscraper designers still consider The Illinois a fascinating concept, inspiring today’s advancements in height, stability and materials.

3. The Shimizu Mega-City Pyramid (Japan, 1990s)

Tokyo’s land scarcity has led to some impressive design concepts, but few are as awe-inspiring as the Shimizu Mega-City Pyramid. Designed by Shimizu Corporation, this pyramid was intended to house one million people within a floating structure over Tokyo Bay. While still theoretically possible, the construction would require next-gen materials (like carbon nanotubes) and a colossal budget.

4. The Volkshalle (Germany, 1930s)

Commissioned by Adolf Hitler and designed by Albert Speer, the Volkshalle or "People’s Hall" was meant to be a massive dome in Berlin, symbolising the power of Nazi Germany. Planned to be over 16 times the size of St. Peter’s Basilica, this hall never made it to reality due to the fall of the regime in WWII. While an uncomfortable part of history, the design is a sobering reminder of how architecture is tied to politics.

5. The Sagrada Familia, Completion Vision (Spain, 1882-present)

While the Sagrada Familia in Barcelona (pictured top and bottom) is famous as a partially completed building, architect Antoni Gaudí’s original vision goes beyond what’s currently visible. Gaudí intended far more elaborate facades and towers, which ongoing construction aims to achieve by 2026. However, financial, political and architectural challenges have prevented its full completion for over a century.

How these projects shaped modern architecture

Apart from Gaudi’s famous project, which is still under construction, the influence of these abandoned projects still persists. Concepts like Tatlin’s Tower or The Illinois have pushed engineers to innovate in materials and structural technology. By daring to design beyond practicality, architects have also created visions that inspire creativity in the field. Equally as important, the abandonment of projects like the Volkshalle shows the impact of architecture on collective identity and the importance of designing responsibly.

In an industry where delays, budget cuts and public opposition can all jeopardise projects, these historical examples offer lessons for today's construction professionals. Planning for example, for adaptable structures can help projects stay viable in spite of changing technologies. Projects like the Shimizu Mega-City Pyramid remind us of the importance of environmental considerations and the potential of renewable materials. We can also learn from the backlash against politically charged structures.

That said – what else is likely to remain unbuilt? Let’s look at a couple of possible examples

Unbuildable projects that could shape the future

1. The Mars Colony Concept

Companies like SpaceX have proposed building colonies on Mars. While the idea seems far-fetched now, it’s comparable to the once "impossible" skyscrapers or Tokyo's floating pyramid. If realised, these colonies could redefine construction in extraterrestrial environments.

2. Submerged Cities

Climate change is driving interest in submerged urban environments, with experimental concepts for underwater cities surfacing. Like the Shimizu Pyramid, the key will be groundbreaking materials and a balance of sustainability and practicality.

To sum it all up, these unbuilt constructions, though consigned to history, reveal the boundless creativity and daring of architects and builders throughout the ages. While budget constraints, technological limits and political turmoil have sidelined their visions, they continue to inspire us, pushing the limits of what construction might achieve in the future. Exploring these projects reminds us that the boundary between visionary and possible is always shifting. Who knows which of today’s “impossible” projects might become tomorrow’s reality?