Beyond the Pillars of Hercules

In Inferno XXVI Dante Alighieri mentions Ulysses in the pit of the Fraudulent Counsellors and his voyage past the Pillars of Hercules. Ulysses justifies endangering his sailors by the fact that his goal is to gain knowledge of the unknown. After five months of navigation in the ocean, Ulysses sights the mountain of Purgatory but encounters a whirlwind from it that sinks his ship and all on it for their daring to approach Purgatory while alive, by their strength and wits alone.