Imagine a construction 100 metres taller than the Eiffel Tower, significantly wider and in perpetual motion. This is Vladimir Tatlin's Monument to the Third International. Designed in 1920, it is the greatest piece of architecture never built.
Now, London's Royal Academy has commissioned a 1:40 scale model of the tower, by artist Jeremy Dixon, to sit in its open-air courtyard and welcome visitors to the gallery.
It is an impressive sight. But at just 10 metres high, it is a mere echo of Tatlin's monstrous 400m high Constructivist model, with its distinctive twisting double helix design (you can see pictures here).
Tatlin's Tower was designed as a celebration of Bolshevism, assisting Lenin in the propagation of the revolutionary tradition and commemorating the 1917 uprising, in much the same way that the Eiffel Tower does the French Revolution.
When the state came under Bolshevik control - in a revolution that saw the Winter Palace captured and Tsar Nicholas II executed - the arts came with it. Tatlin's objectives (and indeed those of all Soviet artists of this era) were to promote the regime in a way that could be perceived as collective. It was no easy task to create a structure that captured the huge influence of the party, its ruthless ambition and desire to be at the centre of world government.
Tatlin turned to time itself for inspiration. He designed a space for offices, meeting rooms and a propaganda centre, housed in one of four geometric shapes. These were intended to rotate at the speed of an hour, day, month and year, essentially making it the world's biggest perpetual calendar.
The tower was to promote Bolshevism as a regime in motion - progressive, active and ambitious. Its flowing spiral design was intended to suggest the resolution of all earthly conflicts (presumably by the conversion of all countries to Communism), and its almost skeletal structure hinted at the idea of man and machine as equals in a classless society.
Tatlin's tower was both a Soviet Utopia - a vision of the bright Bolshevik future - and a fully functioning government building. It was hailed by his contemporaries as an artistic revolution and opened the doors to an exchange of ideas between Moscow and Berlin. Such luminaries as George Grosz paraded signs around the streets, reading 'Long Love Tatlin's Machine Art'. This was Constructivism at its most daring and egotistical -- the progress of art into industrial production, albeit under the watchful eye of the state.
Needless to say, Tatlin's vision was destined for failure. He was not an engineer or architect, so the building was structurally questionable. And there was a shortage of materials, particularly iron. The popularity of Constructivism was also on the wane.
Today, Tatlin's Tower is often hailed as a symbol of modernism's decline: a too-ambitious project, which encapsulated the arrogance of the age. But it can also be viewed as a symbol of experimentation and collective hope. For this was the first true Communist building (albeit never built) - a Bolshevik wonder of the world to rival the Tower of Babel and Hanging Gardens of Babylon, from which is draws inspiration.
It has also influenced many artists. The work of Zaha Hahid and Richard Rogers has echoes of Tatlin - and Rogers' Pompidou Centre in Paris must owe something in its dynamic design to his vision.
Anish Kapoor, too, has taken inspiration from Tatlin's Tower for his ArcelorMittal Olympic sculpture, designed for the London 2012 games in Stratford. (Although with the majority of the cost being covered by steel tycoon Lakshmi Mittal, it can hardly claim any anti-capitalist leanings.)
And in the Far East, imposing megastructures are rising out of ancient cities - their sculptural steel frames a modern interpretation of Tatlin's radical concept.
Did Tatlin ever intend his tower to be built or was it destined to live in the mind? We may never know. But one thing we can be sure of: it has endured where many political regimes have fallen.
The model of Tatlin's Tower is on display at the Royal Academy until March 2012.