Teenage climate activist Greta Thunberg landed in Portugal after 21 days at sea.

She will be heading to Madrid for the COP25 and is ready to fight for the cause.

She said people are failing to grasp the anger of the younger generation.

And she also has a warning for politicians.

"I think people are underestimating the force of angry kids," said Thunberg, according to the Associated Press.  "If they want us to stop being angry, then maybe they should stop making us angry."

The impact of her protests has already spread to Madrid. Extinction Rebellion protesters rallied in a fountain central to the city.

They were calling for action to be taken against global warming as the COP25 conference went into its second day.