Oceania Marina: 16-Night Transatlantic

Miami cruise port, officially called PortMiami, is the busiest cruise port in the world by passenger volume. Millions of people pass through here every year, and nearly every major cruise line uses it as a home port.

Cadiz is the actual cruise port marketed as "Seville (Cadiz)" by cruise lines because Seville, Spain's fourth-largest city, is the primary day-trip draw from this port. Cadiz itself is one of Europe's oldest continuously inhabited cities, perched on a narrow peninsula jutting into the Atlantic on Spain's southwestern coast.

Cartagena is a historic port city of about 215,000 people on Spain's southeastern Mediterranean coast, in the Murcia region. Founded by the Carthaginians in 227 BC (as Carthago Nova), the city has been contested by Carthaginians, Romans, Moors, and Spanish kingdoms, and its layered history shows in the archaeological sites scattered through the compact center.

Barcelona cruise port is the busiest in the Mediterranean, handling millions of passengers a year across multiple terminals. The city behind it earns that traffic.

Marseille cruise port is France's busiest and one of the major stops on western Mediterranean itineraries. The city is France's second largest and its oldest, founded by Greek sailors over 2,600 years ago, and it has a rougher, more authentic edge than the polished Riviera towns further east.

Nice is the capital of the French Riviera, a Mediterranean city of about 340,000 people wedged between the Maritime Alps and the Cote d'Azur coastline. Cruise ships anchor in the bay at Villefranche-sur-Mer, a small harbor town about 6 km east of Nice, or occasionally dock at Nice's own port.

Florence (Livorno) cruise port is the main Tuscan stop on Mediterranean itineraries, but it's worth being clear about what you're actually docking at. The port is Livorno, a working industrial city on the Ligurian coast, about 85 kilometers west of Florence.