Lisbon was for many years Europe's main portal of debarkation for the rest of the planet. Ships captained by Portuguese explorers like Bartolomeu Dias, Vasco da Gama, and Ferdinand Magellan skittered across the globe, hauling treasure home and making Lisbon a global capital. So it's appropriate to arrive by ship. Cruise to Lisbon, situated on a wide bay where the Tagus River meets the Atlantic, and the white facades of its ancient neighborhoods lead uphill to the iconic Castelo de Sao Jorge. Other landmarks include the World Heritage Sites of Belem Tower and Jeronimos Monastery, both built in Lisbon's native Manueline architectural style.