The global climate strike kicked off Friday morning in Australia with “well over” 300,000 people gathering across the country, according to organizers. Climate activists are expected to gather in cities and towns around the world Friday in what organizers have predicted will be the biggest day of climate demonstrations in history. It’s the third global climate strike inspired by 16-year-old Greta Thunberg. Thunberg tweeted early Friday: “Incredible pictures as Australia’s gathering for the #climatestrike... Australia is setting the standard!” Tens of thousands of people have been pictured gathering in the streets of cities including London, Berlin, and Nairobi. Organizers say they expected people in 150 countries to join the global climate strikes throughout the day.