"We are getting bigger and bigger and our voices are being heard more and more, but of course that does not translate into political action," teen climate activist Greta Thunberg said before heading to a Fridays For Future march in Madrid.
The rally, which is expected to draw tens of thousands of young people, takes place as important climate talks are ongoing at the UN Climate Summit (COP25).
"I sincerely hope that COP25 will lead to something concrete," Thunberg said, referring to the urgency of the climate crisis.
Answering a question from the audience, Thunberg said climate and social justice should go hand-in-hand.
According to the 16-year old, some people are afraid of change and change is what young people want -- "that’s why they’re trying to silence us," Thunberg said.
After a four-week journey involving crossing the Atlantic on a catamaran and an overnight train from Lisbon, Greta Thunberg arrived in the Spanish capital earlier on Friday.
In just over a year, Thunberg has inspired younger protesters in a global movement demanding action to slow the atmospheric warming that climate scientists say could ultimately endanger the survival of industrial societies.
Stepping off the night train Lusitania at Chamartin train station in the Spanish capital, the 16-year-old Swede completed a hastily arranged expedition to a UN conference originally planned in Santiago, Chile.
Thunberg was met by a crowd of reporters but did not speak as she left the train.
The Lusitania, which runs daily, is the only direct train link between Lisbon and Madrid and takes nine hours to travel overnight between the capitals.
The annual summit kicked off on Monday with a call from UN chief Antonio Guterres not to be the “generation ... that fiddled while the planet burned”.
But Thunberg says the climate talks are failing.
At the last UN climate event in September, she harangued delegates, demanding: “How dare you?” and declaring, “You have stolen my dreams.”