Kazakhstan climber Denis Urubko thought that K2 was the hardest challenge in many ways of the 8000m mountains. Recently he completed all 14 8000m mountains when he made the summit of Cho Oyu.
He felt that K2 took him to his limit physically and mentally. He had to remind himself all of the time why he was doing it. It took an unbelievable amount of energy from him to climb K2 in 2007.
He considered that Cho Oyu as the most dangerous of the 8000m mountains. He made the summit this year. He thought this because it was the last of the 8000m mountains that he needed to climb. Also he took a more dangerous route than the normal one that is used. He did this so as to make a point that he had made all the 14 8000m mountains. Normally Cho Oyu is considered an easier 8000m mountain.