Scotland's capital city has barely changed over the last 150 years. Shopping centres, offices and homes have come and gone but largely Edinburgh remains the same.

Imagine it had embraced some of the planned transformations though: a capital city with an overhead walkway; one that had attractions like the London Eye and people could travel there by hovercraft, extended trams or even on a motorway through the city centre.

Maybe the last suggestion is too similar to the city further along the M8, but while Edinburgh can proudly parade landmarks like the castle and the Usher Hall there are some projects which have not joined the city skyline.

Here we take a look at just a few of those which would have changed the face of Edinburgh but ultimately did not come to pass.

An alternative proposal which may even have helped pedestrians hoping to avoid the tram chaos brought to Edinburgh's busiest street but one that half a century ago became a recurring theme over the following decades.

The proposals came in two forms: the first showed an elevated walkway, in basic terms built along the street, in basic terms: a bridge running along the buildings instead of across a road, with the front facades being updated.

Any previously unused top floors and balconies of the buildings all being brought to the fore (as mentioned in this article) with this second level giving a new aspect to Princes Street for shoppers and visitors rather than having to walk in at ground level and up inside the buildings.

As you can see above it may have freed up the number of pedestrians walking along the pavement below. Though as one commenter on a Hidden Glasgow forum points out: it was never really shown how the walkways would connect over the side streets, whether it would be bridges or steps up and down each block for crossing the road.

However, the second proposal seemed more radical. The demolition and replacement of every building on Princes Street (a fact pointed out on the same forum) was mooted and the road would run underneath the area.

A more collective look of the buildings together and an underground motorway is pictured below.

The motorway underneath Princes Street was only part of the paved revolution for Edinburgh which would have seen the city centre connection form part of a ring road forming around the outskirts in the 1960s.

According to one blog this would have run though "Haymarket, Tollcross, the Meadows, St Leonards, Waverley, Leith Street, Inverleith and Craigleith". The ring road would also have linked directly to the M8.

Former city council leader Donald Anderson told STV: "The last remnants of that idea were the proposals to run the 'Western Relief Road' into the city and these were only defeated in 1986. I actually voted against it when I was first elected to the council.

"These were big ideas and I can understand why they were drawn up, but they were of course bonkers in practical terms and the city was saved from them by very effective community campaigns."

You can see in the map below how the ring road would have surrounded the city.

Further out from the city centre though lays other landmarks and a bridge (or two) to the Kingdom of Fife and beyond. But there could have been another attraction down by Portobello.

It would have been part attraction and part public transport but plans for a hovercraft were dashed after being sunk by a City of Edinburgh Council sub-committee despite support from Fife Council with docking plans in Kirkcaldy.

Stagecoach spent more than a decade planning to run a regular service of the hovercraft between Kirkcaldy, Fife and Portobello, Edinburgh with journey times of less than 20 minutes and the potential for linkage to bus services and depots.

Even despite a "successful" trial used by 32,000 passengers in a fortnight the hovercraft never came to pass.

Instead, since that time, another link is being created with the £1.3bn Queensferry Crossing being used to ease congestion from the existing Forth Road Bridge.

Adverse weather at the start of the year - which affected the FRB that already undergone a month-long closure for repair works - has delayed the new bridge's opening until mid-May 2017, a decade on from the hovercraft trial.

Just along the water at Leith lies a more famous vessel, the Royal Yacht Britannia, but the docks could also have been the site for the Scottish version of the London Eye.

The planned structure would have been 120 metres tall: four times the size of the Christmas wheel in Princes Street, twice the height of the Scott monument but only narrowly smaller than its London equivalent.

At the time, Councillor Tom Buchanan described the proposals for Scotland's National Wheel (a working title) as a "wonderful opportunity" because the cost would be met by the firm who came up with the idea: Great City Attractions.

That was in 2009. There was still talk of the project the following year with an agreed site next to Ocean Terminal by the then-proposed tram stop.

However, in 2010 Great City Attractions went into administration in July 2012 and ceased trading a month later, putting paid to any notion of the wheel making a turn in the city.

It could have been an attraction for thousands of visitors, even one that would have been an eye-opening landmark for the passengers of the hovercraft. Instead you'll have to go elsewhere for scenic views of Edinburgh and further afield.

The site of Leith Docks was also touted as having the potential to bring multi-million selling music stars along from the other end of the M8.

A large scale venue akin to The SSE Hydro was proposed for the area and there were also plans for a venue near the Royal Bank of Scotland's headquarters in Gogar at the other end of the city. Two rival companies even drawing up plans for several options that would host four or five figure crowds.

While the Glasgow venue cost in the region of £125m the idea seemed less feasible in Edinburgh though with an apparent funding shortfall of £100m standing in the way of the council making any progress on the plans.

One promoter told the Edinburgh Evening News the city was in a dire need for a concert venue but argued the proposed site did not work as the area is not as central in Edinburgh as the Hydro is to Glasgow.

It has propelled the castle to host a number of big names over the last few years as well as acts continuing to flog to the Usher Hall, the Playhouse and occasionally Meadowbank Stadium in the past with Elton John playing there this summer.

And Glasgow itself is no stranger to binned plans and proposals that would have changed the face of the city as we know it today.