The protagonists of this episode of Ulisse are men who have changed the boundaries of nations, continents, and the known world, who have been able to broaden the mental and cultural horizons of their era. They are merchants, scientists, adventurers, conquerors and heroes. Alberto Angela from the headquarters of the most prestigious geographical institutes in the world - the Royal Geographical Society of London and the Geographical Society of Villa Celimontana in Rome - will tell us about the exploits of those who dared to challenge the seas and oceans to discover new worlds: from the Vikings to Christopher Columbus, from Amerigo Vespucci, to Captain Cook killed by natives during his 3rd round the world trip. We will also see how an entire people, the Polynesians, managed to colonize the largest ocean, the Pacific, without compasses or maps.