TORONTO — Walk into the sprawling new addition to the Royal Ontario Museum and the first thing you notice is that nothing appears as it should at Canada's largest gallery.

Walls lean into each other, windows stretch into thin strips, ceilings soar to dizzying heights, pillers tilt askew and corners suddenly emerge with dark, intimate retreats.

But the off-kilter sensibilities offer a surprisingly contemplative space inside the massive crystal-shaped structure that has transformed the architectural landscape of one of Toronto's main thoroughfares.

Renowned architect Daniel Libeskind says he wanted the $270 million addition, making its debut to the public on Saturday, to offer a myriad of spaces that surprises its visitors.

"One will come back again and again and it will always be a new building because it offers completely new perspectives," says Libeskind, a New York based architect also tabbed to to rebuild New York's World Trade Center site.

"Each perspective is unique and it offers new framed views also of the things we really know but from an angle that is very unexpected."

The sprawling structure, named the Michael Lee-Chin Crystal, adds almost 16,200 square metres (25 per cent) to the Royal Ontario Museum, home to Canada's largest collection of dinosaurs, Near Eastern and African art, East Asian art, European history and Canadian history.

Lee-Chin is a Burlington, Ont., financier who donated $30 million to the project.

From the outside, wild angles made of 25 per cent glass and 75 per cent aluminum explode from the original structure's staid brick buildings, providing a stark contrast of old and new that is visible from blocks away.

The design was a controversial idea from the moment it was first proposed as one of dozens meant to revitalize the nearly century-old structure. It went through several revisions before construction began in May 2003, but Libeskind - who first concocted the plan by sketching the radical form on a napkin - says that such extravagant displays are what can revitalize an entire city.

"Toronto is a great city - it's not just Toronto the Good, it's Toronto the interesting, Toronto the evolving," says Libeskind, who used to live in Toronto with his Canadian wife and children.

"It's a dynamic city and I think Toronto is one of the great cities of the world and there's no reason it should not accept the challenge of having cutting edge, daring architecture as well."

The public gets its first peak at the addition this weekend when they're offered free admission as part of Toronto's 10-day arts festival, Luminato. But eager viewers won't quite see the final design - none of the galleries have yet been stocked with their full exhibits and final touches to the interior were still being added Thursday.

An informal press tour had reporters wandering the cavernous halls in hardhats, passing the odd artifact and curio while dodging piles of plaster and cans of paint in several of the rooms.

Construction workers handling buzz saws provided a steady soundtrack.

Officials say exhibitions will be installed in phases over the coming months, with the dinosaur gallery among the first to open this winter.

When work is complete in 2009, the addition will boast seven galleries, new retail and dining areas and a new main entrance that extends from the top to the bottom of the crystal, criss-crossed by bridges linking the east and west galleries.

Gov. Gen. Michaelle Jean officially opens the new wing Saturday night following a 75-minute outdoor concert and light show set to take over Bloor street.

Scheduled performers include David Foster, R&B singer Deborah Cox, Metropolitan Opera sensation Isabel Bayrakdarian, acclaimed environmentalist David Suzuki, rapper K'Naan and fiddler Natalie MacMaster.