History of Toronto
In 1998, the six municipalities comprising Metropolitan Toronto – East York, Etobicoke, North York, Scarborough, York, and the old City of Toronto – and its regional government were amalgamated into a single City of Toronto (colloquially dubbed the "megacity") by an act of the Government of Ontario. This was despite a municipal referendum in 1997 that was overwhelmingly against amalgamation. Subsequently, Mel Lastman defeated Barbara Hall to become the first elected mayor of the megacity.
York Mills
In 1953, York Mills, along with North York, was severed from York County, joining other municipalities to form the regional government of Metropolitan Toronto. The area was the site of a tragic accident on March 17, 1960, when five Italian construction workers on a water main project were killed in a tunnel fire. North York later became a borough, and then a city, and was merged with five other municipalities and a regional government to form the new "City of Toronto" in 1998.