Tomorrow night millions of people worldwide will turn off their lights for one hour, to show their support for the environment and clean, sustainable energy.
In New Zealand, Earth Hour kicks off at 8:30pm.
It began in 2007 in Sydney, and has since spread across the world. Organisers say in 2010, 128 countries joined in.
But not everyone took part. ACT On Campus leader Rick Giles caused an internet sensation when he infamously told TV3' Sunrise show he wouldn't be taking part, instead choosing to celebrate 'Edison Hour' by using as much electricity as possible.
"I think my argument is so powerful that it's not necessary to talk about it," he told host Oliver Driver.
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