Oslo city workers began early Wednesday clearing away the mountains of flowers laid round the cathedral in honour of the 77 people killed in twin attacks on July 22, authorities said. The "flower garden" that spontaneously appeared at the foot of the Domkirke the day after the attacks grew in the following 10 days to cover a vast area, about 50 metres (55 yards) long and 30 metres (33 yards) wide, in a colourful symbol of the outpouring of grief and sympathy from across Norway. Thousands of roses -- the symbol of the ruling Labour Party targeted in the attacks -- and other flowers, along with hundreds of candles, lanterns, messages and drawings have surrounded the cathedral in memory of all who died. Anders Behring Breivik, a 32-year-old right-wing extremist, has confessed to setting off a car bomb outside Oslo government buildings, killing eight, then going on a shooting rampage on the nearby island of Utoeya, where Labour's youth organisation was hosting a summer camp. Another 69 people, many of them teenagers died there. Oslo mayor Fabian Stang announced last week that the flowers would be transformed into compost, the candles would be melted down and the other objects would be saved in the national archives. Other small rose and candle sanctuaries have also sprouted up all over Oslo and other cities, on street corners, near the government buildings devastated in the bombing and near the homes and workplaces of the victims.