Monaco's Prince Albert has reached the North Pole on his four-day expedition to highlight global warming.
Prince Albert said it was a "physically difficult" journey
The prince left a base in Russia on Thursday with seven others in the dog-sled expedition.
He planted a flag of Monaco and one of the International Olympic Committee, of which he is a member.
The prince said: "We must try to find solutions [to global warming], with scientists obviously, but at the individual level."
Prince Albert, 48, was following in the footsteps of his great-great-grandfather, Prince Albert I, who made four Arctic trips a century ago.
But Prince Albert is the first head of state in office to reach the pole.
The prince told AFP news agency by telephone that he had seen the effects of global warming during the trip, with some channels to the Pole barely frozen.
"I think everyone by their behaviour can make their small contribution to a global and extraordinary effort," he said.
The prince said the 91km (56-mile) trip had in fact lasted 150km with the need to skirt ice outcrops.
"It was a physically difficult journey because it isn't a straight line. When you have blocks of ice that crash into each other they make pretty impressive little hills to climb," he told AFP.
Two team members fell into icy water at one stage but were unharmed.
Prince Albert became Monaco's ruler last July after the death of his father Prince Rainier.