['Annapurna. Annapurna I – the 10th highest peak in the world tops the list among the hardest mountains to climb. ... ', 'K2. ... ', 'Nanga Parbat. ... ', 'Kanchenjunga. ... ', 'The Eiger. ... ', 'Baintha Brakk. ... ', 'Matterhorn. ... ', 'Mont Blanc.']