This weekend marks the opening of the Canadian Tulip Festival — the best-known and most colourful flower festival in the country.

The event's origins are a part of Canadian history.

The tulips that bloom throughout Ottawa come from The Netherlands as a way of thanking Canada for providing refuge for the Dutch royal family during the Second World War.

Queen Beatrix spent about five years of her early life in Ottawa.  She attended nursery school and Rockcliffe Park Public School in Ottawa before returning home with her family after the war.

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Queen Beatrix spent part of her childhood in Ottawa during the Second World War. ((AP))

In the fall of 1945, in appreciation of Canada's role in liberating Holland and protecting the royal family, the Dutch sent 100,000 tulip bulbs to Canada.  Later Queen Beatrix's mother, the then Princess Juliana, sent 20,000 more. 

The Dutch tulips have been blossoming in Ottawa's parks ever since, though the festival itself didn't officially start until 1953.

The theme of this year's festival is 'kaleidoscope.' a celebration of spring through colour, culture and community.  To drive that point home a giant kaleidoscope has been set up in Major's Hill Park. 

On Saturday organizers are planning a tea party and on Mother's Day a garden party. 

"On Sunday it will be mainly about floral demonstrations, various activities around the floral theme," said festival director Genevieve Menard.

There's also a Lego tent, where kids will be able to unleash their creative side.

"The kids that come - and the adults too, I should say - will be be building things that grow in the garden.  So we have some snails, some worms some birds, a couple of garden sheds, tulips, gladiolas, parrots, anything they want to build," said Robin Sather who is in charge of the tent.

But of course the glorious flowers are the main event.

The festival runs until Victoria Day, May 23.