On Saturday, May 12, 2012, from 18:30, the London Symphony Orchestra gave a free performance of Igor Stravinsky's Firebird and The Rite of the Spring on Trafalgar Square in central London (Valery Gergiev - conductor, Paul Rissmann - presenter).
This was the first event in a new series of annual concerts, the BMW LSO Open Air Classics.
Some of the best views could be had from the steps of the National Gallery.
More info on London Symphony Orchestra's website.