At 8.30pm on Saturday 26 March 2011, Earth Hour will celebrate a worldwide commitment to ongoing change for the betterment of the one thing that unites us all – the planet.

Your journey can start here by signing up and adding your voice to the hundreds of millions across the globe who have already spoken with their actions. Check out the inspiring Earth Hour 2011 video to see what the planet’s voice looks like.

What will you celebrate for Earth Hour 2011?