A weekend of free events is taking place to mark the reopening of the refurbished Royal Festival Hall.
The modernisation cost £91m over two years
The Grade I listed building on London's South Bank has undergone a two-year £91m pound renovation.
The 2,788-seater auditorium now has upgraded acoustics, under-seat air conditioning and increased leg-room.
The events, called The Overture, include a mass busking session led by Billy Bragg and a performance by the London Philharmonic Orchestra.
The events began when 800 choral singers arrived on candlelit barges at dusk on Friday and performed a choral work specially composed by Orlando Gough.
The scheduled events over the weekend include ballroom and Bollywood dancers, jazz musician Harry Beckett and will feature a cast of 18,000 performers.
"This will be the most ambitious participation weekend we have seen in this country for years," said artistic director Jude Kelly.
"It is an opportunity for artists of all kinds to feel they are the centre of our story."