Time magazine has named 16-year-old Greta Thunberg its 2019 Person of the Year. She's the youngest person to be chosen by the magazine.
Thunberg stood before members of the United Nations in September during the U.N. Climate Action Summit, telling world leaders why stopping climate change needs to become a priority.
She has also met with the pope, the president of the United States and inspired millions of people to join her in September for the largest climate demonstration in human history.
She started striking in August 2018, following a series of heat waves and wildfires in Sweden.
Each day for two weeks in the lead-up to that country's September election, she camped outside the country's parliament in Stockholm and handed out leaflets that read "I am doing this because you adults are [expletive]ing on my future."
Thunberg has also been nominated for the Nobel Peace Prize.
"You all come to us young people for hope. How dare you?" Thunberg said during her climate summit address. "You have stolen my dreams and my childhood with your empty words, and yet, I'm one of the lucky ones. People are suffering. People are dying. Entire ecosystems are collapsing."
Time magazine started the tradition of naming a Person of the Year in 1927. Previous winners this decade have included President Donald Trump, Germany's Angela Merkel, Pope Francis and former President Barack Obama.
"We can't just continue living as if there was no tomorrow, because there is a tomorrow," she told Time in the Person of the Year cover story. "That is all we are saying."