SYDNEY - The streets of Sydney and its iconic landmarks, including the Opera House and the Museum of Contemporary Art, became backdrops to the world's largest light festival as the 2015 Vivid Sydney festival was launched on Friday.

Comprising stunning light installations, live music, street performances and public talks, the annual festival is jam packed with activities to thrill the senses.

Currently in its seventh year, Vivid Sydney has grown into a massive event, with projections and installations spanning the city from Circular Quay to Darling Harbour, to The University of Sydney.

Though the rain might have kept some of the crowd at bay, the many multimedia installations were no less impressive in the soggy weather.

The many projects spread throughout the city will encourage a lively atmosphere where families and friends are able to stroll leisurely from installation to installation and soak in the amazing visuals.

The facade of the Museum of Contemporary Art was transformed into a continuously morphing canvas with a light piece titled Mechanised Colour Assemblage, by artists from Australia, France and Italy.

The Customs House also took on a new look with a magical projection titled Enchanted Sydney. The whimsical presentation of Australia's flora and fauna, matched with a touch of mystical and elvish charm, make the historical building a must-see stop.

Among the many large and immersive light projections are smaller interactive pieces that allow adults and children alike to take an active part in the festival.

The external stairway of the AMP building at Circular Quay has been made into a giant keyboard, inviting visitors to jump up and down the multi-coloured instrument and make their own impromptu music.

Another fun piece takes place at Cadmans Cottage, where the building's architecture is brought to life with graphics and games that can be played with in real time by passers-by.

The whole building is monitored using 3D depth-camera analysis, which creates a live digital silhouette of each person in the vicinity.

Not forgetting Sydney's most iconic landmark, the sails of the Sydney Opera House also take part in the light show. The crisp white sails are splashed with bright lights and vibrant colours in an installation created by UK-based digital art and design studio Universal Everything.

The Opera House will also serve as a scenic backdrop to many of the music events and innovative discussions that will be a part of the three-week festival.

Darling Harbour is one of the 13 precincts in this year's festival which has over 60 light art installations and projections.

The 2015 Vivid Sydney festival of light, music and ideas runs till June 8.