Hamilton will once again go dark for one hour this Saturday to celebrate Earth Hour, according to Mayor Charles Gosling.Speaking yesterday, Mr Gosling said all non-essential lights will be turned off for one hour starting at 8.30pm to raise awareness of the amount of non-essential energy used on a daily basis.“I encourage all residents, business and building owners to join us by turning off all lights and equipment that are non-essential,” he said.“I look forward to welcoming everyone to City Hall this Saturday, staring at 5pm, as we celebrate with other countries around the world what has become the single largest voluntary movement creating awareness of the precious environment in which we live.“We each have a responsibility to the planet we call Earth, and we can and must make a difference at home, at work and at play.”