TORONTO - From concerts, to stargazing, to playing board games by candlelight, Canadians found lots of ways to switch off the lights to participate in Saturday night's global Earth Hour.

In Toronto, the iconic CN Tower slipped into darkness at 8:30 p.m. ET, along with many of the skyscrapers in city's financial district.

However, scattered lights were still visible in some of the office towers in Canada's largest city.

At ground level, most stores and fast food joints along Yonge Street, one of Toronto's busiest, were switched on.

Huge crowds gathered at city hall for a free concert in the dark -- for the most part.

The stage was illuminated, although organizers said the lights were high-efficiency LED bulbs and they purchased a quantity of renewable energy -- likely wind power -- to offset the amount of coal, nuclear energy or gas used by the show.

Others in Toronto opted to mark the occasion away from the crowds.

Paul Haines, 32, celebrated by inviting friends to his east-end home to enjoy appetizers and board games by candlelight.

"We don't often do that. I think we're very reliant on technology."

"We don't often have the nice night where we just sit around and talk to people, without background music or background TV," Haines said.

Toronto Hydro reported a usage drop of 15.1 per cent, up from 8.7 per cent during last year's Earth Hour.

Elsewhere across Ontario, power usage dropped six per cent between 8:30 p.m. and 9:30 p.m., said Terry Young of the province's Independent Electricity System Operator.

Earlier in the evening on the East Coast, about 250 people gathered on Halifax's Grand Parade to watch Mayor Peter Kelly turn off the city hall's lights.

The two cities are among hundreds across Canada participating in the event, where people are encouraged to turn off or dim lights to raise awareness about global warming and climate change.

The event is part of an international effort sponsored by the World Wildlife Fund.

Kelly admitted he was a little disappointed that nearby office buildings left their lights on.

"We had thought everybody would be part of this process and, unfortunately, they are not," he said, gesturing to a nearby office tower where many lights remained on.

However, Kelly said when cities turn off municipal buildings' lights it "engages the citizens" and helps people feel they're part of a change in energy use around the globe.

"It shows that they care for their children and their grandchildren," he said.

"It gives us a chance to pause and think and consider what we can do for the future."

Nearby, astronomers trained their telescopes on the night sky, hoping to see stars more clearly.

Quinn Smith, a 59-year-old amateur astronomer, said Earth Hour allows him, "a chance at the night sky without the light pollution that's normally present at a city's centre."

The stars were also sparkling high above Regina, where Steve Bata was responsible for dimming the lights on the Saskatchewan legislature.

Bata said it's important for the legislature -- perhaps Saskatchewan's most recognizable building -- to participate in Earth Hour because it's a symbol that represents everybody in the province.

"Maybe somebody tonight who hasn't heard about this sees the dome in the legislature is off and thinks `Oh, it's Earth Hour and we need to do something at home.' We're part of a global night and it has implications for everybody," said Bata.

"I think it shows that if everybody does a little thing you can be part of a larger change."

Bata said "it's pretty neat" for Saskatchewan to join famous places around the world, like the pyramids, Sydney, Australia and New York City in doing something that "doesn't take that much effort and ... makes a big impact."

In New York City, the Empire State Building was among the landmarks that turned off lights to signal the need for global support of a new climate treaty.

The United Nations building in New York City also went dark Saturday for an hour as part of the international effort to highlight climate change. Sydney, Australia, was the first major city to observe the rolling global blackout.

Nearly 4,000 cities and towns in 88 countries planned to join in the event.