Are there European equivalents of "Route 66"

The Via Regia.

The Way of St. James is the western part of the Via Regia which connects Eastern Europe with the West. This is one of the longest route you can have to visit Europe.

Ancient Roman Roads

I would say that any of the ancient Roman roads would fit your criteria for being mythical. These used to cover most of Europe, and some of them are still usable to date, be it with or without motorised vehicles. If you need help picking one of them, I’d suggest the Appia Antica (Appian Way) which runs along a number of interesting archaeological sights within, and just outside, of Rome.

Looking for a different country? Some ancient Roman roads in Great Britain are currently used as trails for hikers.

One option is the North Coast 500. It is a new route, being promoted as Scotland’s answer to Route 66. It is 500 miles (800 km), starting from Inverness, and following the coast around the north highlands.

It passes through impressive scenery, and plenty of places of historic interest, and other attractions. Most of the roads are fairly quiet, so are also suitable for cycling.

As it is a new route, it is not very well documented yet. But there is a map and GPS track available on the website. And plenty of other road maps are available. Most of the navigation is fairly obvious, as it is the only road in that area.

An other option might be Autoroute du soleil

The route through France to the south coast, it even has a radio show made after it.

The difference with route 66 is that it is still alive.

The longest European route is the E40. It has a length of over 5’300 miles and one can visit 13 European countries and there are even plans to build additional parts.

The highway is interesting because it leads to a lot of frustration in Western Europe because of the daily traffic jams (especially around Brussels), but in the Eastern part of Europe, it is debatable whether it is really a highway: sometimes the road looks more like a paved road with pedestrians crossing.

In the far Eastern part of Europe, one also might have some problems with corrupt police, so one must be a bit careful.

Belgian national television once made a documentary where a crew drove the entire route (stopping now and then) and visiting strange people that live near the road (again East part of Europe). You can find a small report in a newspaper here (in Dutch).

This article entitled Where is Britain’s Route 66? gives possible suggestions for such a route in the British Isles including:

• A1 Great North Road

The Great North Road sounds like the beginning of an adventure. It links two great cities in London and Edinburgh. True to say that in its day, it had a selection of interesting eateries along its route, and much like Route 66, much of the original route has been bypassed, leaving quieter stretches to explore.
Verdict: A genuine contender to the title of Britain’s Mother Road.

• A5 Roman Road

If you stretch things a bit, you could claim that the A5 links London and Dublin, if you count the ferry. These two compare well with Chicago and L.A. It follows the route of the ancient Watling Street built by the Romans, hence it is signposted as ‘Roman Road’ along sections of its length. And there is plenty of things along the route indicating the route’s history, such as coach houses and staging posts. The real trump card however is the Menai Suspension Bridge. This bit of architectural interest makes the A5 a stand out candidate. If only there was a song about it.

A book is also available for Britain’s Route 66. It has over 900 colour photographs and the largest ever collection of memorabilia from the beginnings through today.

Available from Grantham Book services.

Tel: +44 (0)1476 541 080

(I have no association with the above book)

Alternatively:

If you are a biker, you may be interested in Spain’s own Route 66 with the Spanish company Route66Spain. They will introduce to:

A tour of Spain from north to south where you can enjoy the best scenery, sample the best restaurants and especially to make a unique and unforgettable experience in your life.

(I also have no association with this company either)

You may be interested in Via Francigena too.

EDIT: I recently stumbled upon the European Institute of Cultural Routes (dead link, probably this) and apparently its main purpose is to preserve, promote and improve historical/cultural routes in Europe. On the Wiki page there’s a comprehensive list of the routes they monitor:

Major Cultural Routes of the Council of Europe

Pilgrim Routes
    The Way of St. James to Santiago de Compostela
    The Via Francigena between Rome and Canterbury;
Historical and Legendary Figures of Europe
    Saint Martin de Tours, a Symbol of sharing
    The European Mozart Ways between Milano and Salzburg;
Influence of the monasteries
    The Cluniac Sites in Europe;
Vikings and Normans - European Heritage
    The Viking Routes;
Hanseatic Places, Routes and Memorials;
Parks and Gardens, Landscapes;
The Legacy of Al-Andalus;
European Routes of the Jewish Heritage;
The Routes of the Olive Tree;
The Via Regia

Cultural Routes of the Council of Europe

Rural Habitat
    Architecture without Frontiers;
Historical and Legendary Figures of Europe
    The Schickhardt Route;
Military Architecture in Europe
    The Wenzel and Vauban Routes;
The Route of the Castilian Language and its Expansion in the Mediterranean: The Sephardic Routes;
Industrial Heritage in Europe
    Route of Iron in the Pyrenees
    The Central-European Iron Trail[1]

I agree with mouviciel. Europe’s mythical road par excellence is the way of St. James.

If you prefer a drivable road, there is one particulary mythical road in France, the Nationale 7. It is nearly 1000 kilometers long and runs from Paris to Menton, on the French Riviera. It crosses some beautiful spots. The French also call it “route des vacances” (= holiday road). Before the construction of the motorway it was the main axis linking Paris and Southern France. There is a dedicated website.

You can also have a look at the Roman roads. The Romans built an extensive road network in Europe. These roads do not exist any longer. However, it should be possible to mimic their course today. Unfortunately, I think that such trips are not well documented.

The mythical, even mystical, route I think of, is not by car but by foot. It is not even a single route but a network of paths from everywhere in Europe to a single place: This is the Way of St. James.

I never heard of something close to Route 66 in Europe. Though car has an essential role in today’s Europe, its history is relatively young. Famous paths are by foot or by train and they don’t stop at the borders of Europe. Moreover, the most convenient way of travelling was not on ground but by boat. I don’t think that the Mediterranean Sea or the Baltic Sea would qualify as the most famous routes. Garry Vass mentioned Orient Express and Marco Polo. Hippietrail mentioned Silk Road. There are also trade routes for spices, amber, and incense.

One path that is not so famous (yet) but that I would love to follow is the Eurovelo 6 from the Atlantic Ocean to the Black Sea, along the Loire and Danube rivers. It has only one 6 and only two wheels…

I suppose the only real European equivalent is the ill-defined ‘grand tour’. But you’ll be hard pressed to actually find it.
Here’s another question on the grand tour.

That said, there are plenty of semi-epic drives around Europe. In fact, much of Europe is so compact, that you can easily come up with your own epic ride in pretty much any part of Europe, without even having to drive too much.