By Michael Leidig In Vienna

Vienna's most prominent landmark, the Giant Ferris Wheel, which opened more than 100 years ago to mark the golden Jubilee of Emperor Franz Josef, has had a 5.5m euros facelift.

Actor Orson Welles used the wheel in his classic film, The Third Man

The huge investment includes a hi-tech visitor centre and new lighting effects by London's Millennium Dome artist Patrick Woodroffe, aimed at ensuring the wheel continues to dominate the skyline, not just during the day but at night as well.

The Viennese love of the wheel, which they call the "Riesenrad", was shown after World War II when it was the first object to be rebuilt along with St Stephen's Cathedral and the Opera House.

But it became Vienna's best known landmark on the international scene when it was used in the classic Orson Welles film The Third Man, which opened for the first time on 10 March 1950.

May Day celebrations

Welles played the elusive criminal Harry Lime, pursued by his nemesis Holly Martin, played by Joseph Cotten.

We realised we had a responsibility to all those who love the Riesenrad to take the utmost care with any changes

Creative designer Stefan Seigner

The pair meet for the first time in the Riesenrad in one of the 30 giant carriages.

The film, with its moody camera angles, was frequently voted among the top ten best films of the last century and the British Film Institute voted it the greatest British movie ever.

The official opening of the new-look Riesenrad will take place on Wednesday as part of Austria's May Day bank holiday celebrations.

Spokesman for the owners Ingo Dopplinger said: "It was a lot of money but it was well worth the investment, and will mean for the first time in the big wheel's history that we can stay open all year."

"Vienna is bitterly cold in winter so we always had to close before, but with our new modern visitor complex it means this is no longer a problem."

'Modern' redesign

Stefan Seigner, creative designer for the new look wheel, said: "We realised we had a responsibility to all those who love the Riesenrad to take the utmost care with any changes.

We believe people will be very happy with what they see

Spokesman Ingo Dopplinger

"But at the same time we needed to take the necessary steps to bring it into the modern world."

Austrian architect Mathis Barz designed a new entrance area with an all-glass coffeehouse and a shop - as well as an exhibition on the history of the Riesenrad since its opening in 1897.

The new centre also includes a "Wheel of Time" display to keep people occupied who are waiting to take their place in one of the giant carriages.

Located in the newly built "Panorama Pavilion", it presents Vienna history in eight cabins arranged in a circle.

Each cabin represents part of the city's history from the Roman Age through to the Medieval Times, ending with the world wars.

The roof of the pavilion opens up periodically to presents a view looking up at the Riesenrad itself, which although small in comparison with modern big wheels, has an all iron construction which means it weighs in at more than 430 tonnes.

Tourism boost

The upgrade is also a bid to boost visitor numbers at the privately owned attraction.

The wheel has been falling in popularity, and although still the city's fourth most popular tourist attraction with 750,000 guests a year, the owners hope the revamp will raise the numbers still higher.

The new look Riesenrad has its cost, with adults now having to pay more than double the original price.

But according to Mr Dopplinger, the need for the price hike is clear: "We are a privately owned attraction, so we did not receive any public funding for the improvements."

"It means we have to make sure we can cover the costs but we believe people will be very happy with what they see."