The completion of a £30m project which created an underground link between two of Edinburgh's best known art galleries has been hailed as a "momentous" event.
The National Gallery of Scotland will host a Titian exhibition
The Playfair Project aims to bring the National Gallery of Scotland and the Royal Scottish Academy up to date.
The new-look visual arts complex was officially opened on Wednesday.
Sir Timothy Clifford, director general of the National Galleries of Scotland, said it was one of "the most momentous occasions" in the Scottish art world.
"Not only are we celebrating the completion of the Playfair Project, but a very great exhibition," he said.
The National Gallery of Scotland on the Mound is playing host to The Age of Titian, which opens to the public on Thursday.
The exhibition brings together masterpieces by the greatest artists of the Venetian renaissance.
Sir Timothy said that until now Scotland had struggled to bring in the old masters, which require modern facilities to display the paintings.
It has taken five years to bring the two 19th century art galleries up to 21st century standards.
The Royal Scottish Academy has been refurbished
Neither of the buildings had been substantially upgraded since 1910.
However, in one of the largest engineering projects of its kind, the buildings have been upgraded and expanded with the creation of a tunnel.
One of the first jobs was to replace the original timber foundations with 350 litres of concrete. Staircases had to be levelled and new entrances created.
The underground link between the galleries, known as the Weston Link, features a glass-panelled entrance overlooking Princes Street Gardens.
Sir Timothy, novelist Ian Rankin and leading figures from the arts world received a tour of the new facilities on Tuesday.
The project also included hi-tech education facilities, new cloakrooms, multi-media tools and a restaurant.
The RSA has been restored and refurbished to create the largest space devoted to temporary exhibitions in Europe outside of Berlin.
Brian Ivory, chairman of the board of trustees of the National Galleries of Scotland, said 21st century technology was being used to help people enjoy and understand the art on display.
He said: "What we are getting today and henceforth is proper education facilities to brighten the lives of schoolchildren."
Speaking at the opening of the tunnel First Minister Jack McConnell said the new gallery spaces would allow more people to access the finest culture Scotland could display.
He said: "This was an ambitious project and represents a significant achievement for the National Galleries of Scotland.
"The whole nation can be proud of these new facilities.
"This new project will provide access to excellence and to some of the greatest art works from around the world.
"This is another achievement for devolution in Scotland. It signals our ambition to be the best small country in the world to visit."