Although it had a long gestation period, through a series of aboriginal settlements and the construction of a French fort here in 1720, Toronto was officially born 175 years ago today. That's when a small community, known as the Town of York, was formally incorporated as the City of Toronto.

Much has changed since March 6, 1834. A municipality of fewer than 10,000 people, mainly from the British Isles, has blossomed into a city of more than 2.5 million, with residents from virtually every country on the planet.

Today and over the weekend, Toronto celebrates that transformation though songs, poetry, film screenings, photography displays, theatrical performances, a book festival, historical exhibits, re-enactments and more.

Entry to all eight of the city's historic museums will be free this weekend. And a new commemorative book about Toronto is being launched at City Hall.

In something of a time warp, Mayor David Miller is to debate Toronto's radical first mayor, William Lyon Mackenzie, played by actor Eric Peterson, better known as Oscar Leroy on television's Corner Gas. (One wonders if Peterson will manage to resist deploying Oscar's favourite term for detractors: "Jackass.")

In another re-enactment, the Queen's Own Rifles are to demonstrate a 19th century military skirmish using Nathan Phillips Square as a battlefield.

This all serves as a useful reminder of the abundant history that lies quite literally in our own backyard. And there's more to come. Three years from now, in 2012, Toronto will have an opportunity to mark the 175th anniversary of the Rebellion of 1837, when an armed mob led by former mayor Mackenzie charged down Yonge St. in a doomed effort to topple the provincial government.

An even more important anniversary will be marked in three years: the bicentennial of the War of 1812, in which an American invasion was repelled. Had the invasion succeeded, we would now all be Americans.

That conflict saw the destruction of Fort York and the looting of this municipality (in retaliation for which the White House was burned in Washington). Two decades after the end of the War of 1812, and fully recovered from its ravages, Toronto was incorporated as the first city in the colony of Upper Canada.

Its boundaries were marked by the shore of Lake Ontario, Bathurst St. on the west, Dundas St. on the north, and Parliament St. on the east. Today the city encompasses a territory more than 100 times that size, and it serves as the hub of one of the biggest and most dynamic urban regions in North America – the Greater Toronto Area.

Residents seldom stand still to consider how much and how quickly Toronto has changed over the 175 years. That's understandable amid the many more immediate cares and concerns of everyday life.

But commemorating historical events like Toronto's 175th anniversary provides an opportunity for us to gather and stand where others stood before us. Remembering the past is a useful step toward moving forward together.