It was a night that had to be seen to be believed.
The concept was simple. Helsinki, the capital city of progressive and environmentally aware Finland, would for one hour be a beacon of darkness for the world.
The idea of turning lights out for an hour was not Finland's of course. But the scale was original: To create a total "Blackout" area free of all light and power consumption in the Helsinki city centre.
The City Council was the main driver of the campaign, seeing it as a great opportunity to not only draw attention to environmental issues and bring the community together in the recession but also to put on a cheap feel-good event.
Rather than just turn non-essential lights out like most other participating cities, the Council - with support from Finnish energy conservation NGO Suomi AFD - decided that in Helsinki all public lighting would be switched off unless directly related to emergency services.
Together they organised an army of volunteers to direct traffic at busy intersections, explain to people why the buses and trams weren't running and maintain a presence around the darkened city to ensure public safety.
Private homes and businesses were always going to be difficult to persuade, but it seemed by Friday - after a campaign across newspapers, radio and on television - that the cause had won broad support in the community.
Even Big Brother superstars, in a rare public appearance, urged people to switch off TV sets and instead watch them perform their daily routines live in a specially built eco-friendly cage in the city centre.
They need not have bothered. Late last week TV and radio took the unprecedented move of cancelling all programming for the hour (other than an occasional brief message to explain why there was no broadcast).
Once the media was behind the campaign, local bars, nightclubs and even churches came to the party, organising black or environmentally themed events and services.
With all the support and publicity the Finnish Earth Hour promised to be the best in the world.
My girlfriend Sanna and I left our apartment just after the event began, heading for a friend's party on the other side of the city centre.
The truth is we had forgotten all about Earth Hour.
In our defence, as the news here is in Finnish and Swedish I was only vaguely aware of the event, while Sanna was preoccupied all week studying for an exam.
It took us a couple of blocks to even realise what was going on. I had noticed that there were no traffic lights but didn't think anything of it. I knew that I was having trouble seeing the footpath in front of me, but just assumed it was related to the absence of snow.
It shows how quickly the mind adapts to a given reality (or perhaps just indicates that we had been drinking).
It wasn't until we saw a dark figure directing traffic at an intersection that we figured out what was happening.
As it turned out, the timing of our walk could not have been better: It allowed us a close up view of the darkest Earth Hour on the planet as it unfolded.
In its own way, it was spectacular.
First, it was much darker than usual. In fact, it was almost impossible to see anything. Aside the light from one or two negligent homes and business and the flashes of cameras, the centre of Helsinki was plunged into a medieval darkness.
Unlike photos of Earth Hour in other cities which show merely a dimmed version of cities at night, photos taken in the blackout area that night are completely black (see picture above of Sanna and me in front of the Helsinki Towers).
Excited by the success of the event and the eerie darkness the atmosphere was electric. All over the centre people were outside drinking, singing and accidentally bumping into each other.
Everywhere I looked usually shy and reserved Finns were starting up conversations with strangers and helping each other to their feet. Whether or not this was due to numerous cases of mistaken identity as cynics said, Helsinki was still an incredibly friendly place to be that night.
It seems, however, that the organisers had not anticipated such support from the public. The tremendous success of the campaign caused some problems.
The most serious issue was the number of cars in the centre. Apparently a combination of interest in the event itself from those living outside the city and the temporary suspension of public transport dramatically increased traffic, rather than reducing it as hoped.
Not only were there more cars, but in the spirit of the event many drivers were driving along the blackened streets with their lights off.
Added to this, from what we saw - which was admittedly very limited because of the darkness - the army of volunteers did not materialise. It seems that many were unable to reach the city centre without public transport, while others said that the all black uniforms made it too dangerous to stand on roads and direct traffic.
Any chance for a last minute volunteer recruitment or warning to leave their cars at home was impossible because the radio and TV stations were dead.
Across the city centre over half of the intersections we passed were without any traffic control at all, relying instead on the patience and extra care shown by Helsinki's motorists.
I was surprised that we saw only one accident - a nose to tail - on our walk.
Although in the end there were three times more minor car crashes than on a typical Saturday, the absence of any serious accidents is a tribute to those behind the wheel that night.
Despite the anarchy on the roads and the vastly increased number of people admitted to hospital with minor injuries, the event was a great success. Power consumption fell dramatically and people all over Helsinki joined together in support of a worthwhile cause.
As hoped, the event not only drew attention to environmental issues, but also demonstrated that living without some of even the most basic conveniences that we take for granted is not only possible, it can actually be fun.
In the depths of a global recession - when people across the world are questioning an economic model that in its thirst for permanent economic growth is threatening the very basis of life on earth itself - perhaps Earth Hour will mark the beginning of an enlightened dark age.
Next year AFD are planning an even bigger event - I can't wait.