In 2006, Michael performed a free concert for NHS nurses in London to thank the nurses who had cared for his late mother. He told the audience: "Thank you for everything you do — some people appreciate it. Now if we can only get the government to do the same thing." In 2007, Michael sent the £1,450,000 piano that John Lennon used to write "Imagine" around the United States on a "peace tour", displaying at places where notable acts of violence had taken place, such as Dallas' Dealey Plaza, where US President John F. Kennedy had been shot. He devoted his 2007 concert in Sofia, from his "Twenty Five Tour" to the Bulgarian nurses prosecuted in the HIV trial in Libya. On 17 June 2008, Michael said he was thrilled by California's legalisation of same-sex marriage, calling the move "way overdue".