Kennedy's cancellation of the "Sensation exhibition" (scheduled at the NGA from 2 June 2000 to 13 August 2000) was controversial, and seen by some as censorship. He claimed that the decision was due to the exhibition being "too close to the market" implying that a national cultural institution cannot exhibit the private collection of a speculative art investor. However, there were other exhibitions at the NGA during his tenure, which could have raised similar concerns. The exhibition featured the privately owned Young British Artists works belonging to Charles Saatchi and attracted large attendances in London and Brooklyn. Its most controversial work was Chris Ofili's "The Holy Virgin Mary", a painting which used elephant dung and was accused of being blasphemous. The then-mayor of New York, Rudolph Giuliani, campaigned against the exhibition, claiming it was "Catholic-bashing" and an "aggressive, vicious, disgusting attack on religion." In November 1999, Kennedy cancelled the exhibition and stated that the events in New York had "obscured discussion of the artistic merit of the works of art". He has said that it "was the toughest decision of my professional life, so far."