Southeast Spain's seaport of Cartagena is a large naval base on the Mediterranean coast. The city was founded in 220 B.C. and boasts Roman ruins, mosaics and murals.

Seven miles outside of historic Athens, the Greek coastal city of Piraeus lies upon the sparkling waters of the Aegean Sea and is the largest passenger port in Europe, servicing nearly 20 million passengers per year.

Three hours north of Auckland, a chain of verdant islands meet glittering turquoise waters in the Bay of Islands. This subtropical paradise will astound you with its abundance of natural beauty and marine life. Sail to the Bay of Islands, and you'll find plenty to see and explore. Hike to stunning Rainbow Falls, kayak along the shores of New Zealand's lush coastline, and keep an eye out for whales, dolphins, penguins, and a variety of colorful parrots.

Greenland, the world’s largest island, offers travelers an experience that feels like stepping onto another planet. Vast ice sheets, towering glaciers, and deep fjords stretch across the horizon, creating a landscape that constantly shifts with the light. During summer, the Midnight Sun casts a golden glow well past midnight, while winter brings months of darkness lit by vibrant displays of the Northern Lights.

A charming city nestled on the banks of the Rhine, Mainz, Germany lies southwest of Frankfurt and is replete with historic buildings and famous museums. The city's Altstadt district meets the river's edge and boasts a variety of beautiful and fascinating landmarks.