Working with the rendering agency CG Orange, the developer Barratt Homes has superimposed 3D images of several proposals reported by Guardian Cities over Google Earth images of where they would have stood, and our design team has allowed you to switch back and forth.
So heres your chance to see what London might have looked like had some of these designs made it off the drawing board.
An airport on the Thames estuary isnt as original an idea as Boris Johnson might have you believe. A 1934 plan proposed the Thames itself host a new airport, directly next to the Houses of Parliament in between Westminster and Lambeth bridges. It was to be tall enough to accommodate passing ships and suitable for single-propeller aeroplanes.
For its rendering here, the CG Orange agency adapted the original design with a new ramped runway, in order to give planes more time to take off, and a riverside check-in lounge, in addition to the storage (of planes and fuel) that was planned for underneath the runway and elevators in the support pillars.
This luxury hotel, designed by the architect CJ Phipps, was open from 1899 to 1940 and originally run by the infamous hotelier César Ritz; the head chef was Auguste Escoffier, and it competed with the Savoy (which the pair previously ran) for prestige. In the second world war it was badly damaged by bombs, and was eventually entirely demolished by 1958. The High Commission of New Zealand now stands in its place.
In the early 19th century, Sir Frederick William Trench, an MP and soldier, had an idea to commemorate the defeat of the French at the recent Battle of Trafalgar and the earlier Battle of the Nile.
His idea? A pyramid at the top end of Whitehall. Blueprints show that it would have been taller than St Pauls Cathedral, with 22 steps – one for each of the years the English and French had fought in those conflicts. Instead, the land was cleared and a statue of Nelson installed. The dream of a London ziggurat was over.
Nearly 50 years ago, with bus use falling and cars clogging up the streets, London briefly toyed with the idea of scrapping many of the buses entirely, and replacing them with (sing it) a monorail … monorail … monorail!
Proposed by Brian Waters and endorsed by the Conservative opposition in the GLC, the monorail would have had four large loops. Despite that early political support, the plans was quietly abandoned within a couple of years.
After the Great Exhibition of 1851, there were a number of plans for what to do with the structure (originally located in Hyde Park, but subsequently moved to Sydenham, in what is now known as Crystal Palace Park).
One idea, rather obtusely, was to build Londons tallest skyscraper: Charles Burton drew up a plan for a 1,000 ft high building, which, given the height of the south London location, would now make it 100ft higher than the Shard. There were to be vertical railways (we might now call them elevators) to the summit, and a giant clock halfway up.
A HUGE pyramid in Trafalgar Square and an airport over the River Thames next to the Houses of Parliament are among the bizarre landmarks which were planned for London but never built.
Some of the capitals most ambitious construction projects which never saw the light of day but would have transformed the citys skyline have been revealed.
In a series of pictures created by property development company Barratt Homes, it is possible to see what the city would look like if those plans had been realised.
Among the most astonishing designs for London was a 300ft pyramid to be built in the middle of Trafalgar Square.
The humongous landmark would have soared above St Pauls Cathedral to become the tallest building in London at the time.
Designed in the 1820s, the pyramid would have commemorated Britains victories in the Battle of Trafalgar and the Battle of the Nile.
Back in 1934, plans were drawn up for an airport built over the River Thames right next to the Houses of Parliament.
The huge landing field would have stretched 700m (0.4 miles) from Westminster Bridge to Lambeth Bridge.
Lifts were to be built into the huge pillars to take passengers from the ground to the runway, while the airport would have been high enough above the Thames to allow ships to pass underneath.
Crystal Palace Park in Sydenham, southeast London was once home to a huge glass and iron structure built in 1851 for the Great Exhibition in Hyde Park.
The mammoth structure — which became known as Crystal Palace — stood until 1936 when it was destroyed by a catastrophic fire.
But before the building was moved from Hyde Park to Sydenham, plans were made as to what to do with it.
One unbelievable idea put forward was to create a 1,000ft skyscraper with a lift in the middle to carry visitors.
Once at the top, visitors would have been treated to an incredible view across the city, taller than the Shard is today.
But unfortunately, the structure was never built, and modern architects believe it would most likely have collapsed under its own weight.
And in the 1960s, one scheme was for a Central London Monorail to carry passengers above the citys streets.
The Carlton Hotel was one of the capitals most luxurious establishments until it was badly damaged by bombing during World War 2.
Built in 1899, the elegant site on the corner of the Haymarket and Pall Mall was closed in 1940 and finally demolished in 1957 when it was replaced by the High Commission of New Zealand.
Barratt Homes described the designs as: “Five of the most jaw-dropping designs that would have completely changed the landscape of London.”