 Complete the following phrase:  The World Snooker Championship reverted to a knockout tournament format in 1969, beginning what is now known as snookers modern era. It has taken place annually since then, with every championship since 1977 staged at the Crucible Theatre in Sheffield. Under a format that has remained largely unchanged since 1982, 32 players reach the Crucible each year: The top 16 players in the world rankings qualify automatically, while another 16 players win places through a qualification tournament. Only three qualifiers have ever won the tournament: Alex Higgins in 1972, Terry Griffiths in 1979 and Shaun Murphy in 