A major retrospective of the supersized sculptures of Indian-born artist Anish Kapoor opens this week in London, with the venue's 19th century buildings under attack from a giant cannon. More than 30 tonnes of blood-red wax will be fired from the cannon onto the walls of a corner of the Royal Academy of Arts during the three months of the show. The exhibit, 'Shooting into the Corner', causes startled spectators to jump when it fires every 20 minutes -- and leaves a constantly growing crust on the white walls. In the next room, a huge yellow fibreglass and pigment depression in the wall ('Yellow') assaults the senses. One of the curators, Adrian Locke, said that in a show full of physical challenges, the cannon had presented the biggest problems, as it sometimes spatters stray splashes of wax onto the 160-year-old ceiling above the wall. 'We have never done this before, this was a new challenge for us,' he said. 'We have taken measures to protect the fabric of the building, but we are hoping the wax will come off the ceiling easily. It is going to be quite a lot of work when the time comes though.' In other highlights, a block of raspberry-coloured wax snakes through the archways of the gallery, coating them with the mixture as it goes. Although static, it gives the impression it is moving. Visitors to the show are greeted outside by a towering arrangement of 76 shiny balls which reflect the Palladian buildings of the courtyard where it is erected. Kapoor said the sculpture, a new work called 'Tall Tree and the Eye', showed he had far more work to come, despite already being granted a retrospective, an honour given to most artists only after their death. 'It feels as though I have yet some work to do... much of the work here today is new,' said the 55-year-old, who won Britain's prestigious Turner art prize in 1991. The exhibition opens to the public on Saturday and runs until December 11. 