Crystal Serenity: 27-Night Mediterranean from Lisbon

Lisbon cruise port is one of the most atmospheric arrivals in Europe. Ships sail up the Tagus River past the 25 de Abril Bridge (a near-twin of San Francisco's Golden Gate) and the Christ the King statue, with the city rising up on seven hills to the north.

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.

Valencia cruise port is Spain's third-largest cruise port (after Barcelona and Palma de Mallorca) and a rising star on Western Mediterranean itineraries. Valencia sits on the east coast of Spain about 350 kilometers south of Barcelona and 350 kilometers east of Madrid.

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.

Rome's cruise port is in Civitavecchia, a working port town about 80 kilometers northwest of the city. That distance is the single most important thing to understand about this stop.

Salerno is the eastern gateway to the Amalfi Coast, one of Italy's most celebrated stretches of coastline. Cruise ships dock at the Stazione Marittima in Salerno's port, a short walk from the city center and the starting point for trips along the legendary coastal road to Amalfi, Positano, and Ravello.

Valletta cruise port is one of the most visually dramatic arrivals on any Mediterranean itinerary. Ships sail into the Grand Harbour, a deep natural inlet flanked by honey-colored limestone walls that rise straight out of the water, with Valletta itself perched on the peninsula above.

Souda Bay is the deep-water port serving Chania, the second-largest city on Crete and arguably the most beautiful town in all of Greece. Cruise ships dock at Souda, a small port town about 7 km east of Chania's historic center.

Athens cruise port is in Piraeus, a busy port city about 10 kilometers southwest of central Athens. Piraeus is its own city, not just a terminal, and it handles cruise ships, island ferries, and commercial traffic all at once.

La Goulette is the cruise port serving Tunis, Tunisia's capital, located on the Mediterranean coast of North Africa about 12 kilometers northeast of the city center. The port sits at the entrance to the Lake of Tunis, a shallow lagoon separating La Goulette from downtown.

Cagliari is the capital of Sardinia, Italy's second-largest island, on the island's southern coast. The cruise port (Porto di Cagliari) sits directly at the edge of the old town, about a 10-minute walk from Piazza Matteotti and the base of the historic Castello district.

Monaco is a sovereign city-state on the French Riviera, just 2 square kilometers in size with about 39,000 residents, making it the second-smallest country in the world. Monte Carlo, its most famous district, is synonymous with wealth, casinos, and Formula 1 racing.

Monaco is a sovereign city-state on the French Riviera, just 2 square kilometers in size with about 39,000 residents, making it the second-smallest country in the world. Monte Carlo, its most famous district, is synonymous with wealth, casinos, and Formula 1 racing.