The Western Mediterranean has among the greatest concentration of art, architecture and archaeological ruins in the world. As you sail through the region, thousands of years of history will be unfolded layer by layer. In fact, there's so much to take in that you might not know where to start. Here are our picks for the Western Med's must-see sights for culture vultures.

Barcelona: Gaudi's Treasures

To visit Barcelona without witnessing the otherworldly designs of Antoni Gaudí would be a crime. The work of the figurehead of Catalan Modernism has become symbolic for the city he was born in back in 1852. Gaudi's fantastical Gothic-style cathedral, Sagrada Familia, is one of Barcelona's biggest attractions. This still-unfinished cathedral is unlike anything you've ever seen, with an interior designed to resemble a forest. Throughout the structure, there are whimsical spiral staircases, stunning stained glass, bell towers and bridges. Another Gaudi must-see is the exterior of Casa Mila also known as La Pedrera, a curvy apartment building that looks like something out of "The Hobbit." Also worth a visit is Casa Batllo, Gaudi's colorful allegory of the legend of St. George the dragon slayer, complete with a roof mimicking dragon scales.

Tip: Most cruise lines run half-day tours that visit all of the stops above.

Marseille: Basilica of Notre Dame de La Garde

The most striking feature of Marseille's Basilica of Notre Dame de La Garde is the 30-foot gold statue of the Virgin Mary (sitting on a 180-foot bell tower/belfry) protectively looking out over her city. Locals call her la bonne mere or "the good mother." The Roman-Byzantine church's mosaics were restored in 2008 after years of damage from candle smoke and the impact of bullets during the liberation of Marseille in 1944. Bullet holes from the battle are still visible on the northern facade of the basilica.

Tip: This is where you'll get the best view of Marseille.

Nice: Matisse Museum

The colorful southern coast of France was a muse for French artist Henri Matisse, who came to Nice in 1917 in the hope the sunny climate would cure his pneumonia. He stayed until his death in 1952. The city of Nice turned a 17th-century villa into a museum showcasing works from various stages of his career. The paintings are complemented by black and white photographs of Matisse at work, as well as his personal belongings.

Tip: Nice is also home to Musee Marc Chagall, and it has stunning examples of his religious-themed work.

Florence: Uffizi Museum

One of the oldest and most famous art museums in the world, the Uffizi is home to Italy's largest and most impressive art collection. The name of the museum, Italian for the word "offices," comes from the palace's original use as an office building, designed by the great Giorgio Vasari for aristocrat Cosimo I de' Medici. It was then used to display the Medici family's large collection of paintings and sculptures and, thus, the Uffizi was born. Highlights of the museum's works include the Madonna of the Goldfinch by Raphael (recently renovated), the Birth of Venus and Primavera by Sandro Botticelli, Battle of San Romano by Paolo Uccello, Michelangelo's Doni Tondo, Titian's Venus of Urbino Bacchus by Caravaggio. For a truly unique experience, book a private tour of the Vasari Corridor, the art-filled secret passage over the Ponte Vecchio that links the Uffizi to the Palazzo Pitti.

Tip: The Uffizi is famous for four-hour-long ticket lines during the busy summer months, so definitely book an organized excursion.

Florence: Accademia

How could you come to Florence and not pay your respects to the most famous man in the city? Seeing Michelangelo's David sculpture is a must. You'll need to visit him at the Accademia, where he stands behind a Plexiglass barrier. While some 6,000 people go there daily for David, they stay to also see Michelangelo's lesser-known sculptures Slaves (an unfinished piece) and St. Matthew. The collection of Florentine paintings ranges from the 13th to the 18th centuries.

Tip: Taking photos of the David is a big no-no, but you can shoot pictures of the replica outside the building.

Rome: St. Peter's Basilica and Vatican Museums

Vatican City, a country unto itself and the seat of the Catholic Church, is a must for any visit to Rome, and it's well worth the trip into the city from the port of Civitavecchia. The Vatican Museums, began by Pope Julius when he put his personal collection of sculptures on display, are a series of museums holding some of the world's greatest art treasures. The very greatest is the Sistine Chapel, Michelangelo's nine-panel masterpiece depicting God's creation of the world, man's fall from grace and other Biblical scenes. St. Peter's Basilica was completed in 1626 and was built on the site of the Old St. Peter's Basilica, a 4th-century church erected over the burial site of Saint Peter. The basilica's nave is the highest of any church, and its interior is elegantly decorated with gold and marble. St. Peter's dome was designed by Michelangelo. Michelangelo's Pieta is another must-see inside.

Tip: During warmer weather, be sure your knees and shoulders are covered (as a sign of respect), or you won't be allowed into the basilica.

Rome: Colosseum and Roman Forum

This is the Rome you read about in history books and watched on screen in Spartacus and Gladiator. A symbol of Imperial Rome, the Colosseum once held more than 50,000 spectators for gladiator contests, mock sea battles and drama performances of Greek mythology. Just west of the Colosseum, the Roman Forum was for centuries the center of Roman life -- first as a marketplace and then as a venue for elections, speeches, government functions, trials and celebratory processions. Exploring these two historic sites alone will give you a good grasp of what life in the Roman Republic was like and how it influences everything from how modern Western cities are constructed to how the United States is governed.

Tip: While it can be tempting to see these sites on your own, take an organized excursion, or hire a private guide. Most are talented storytellers who can provide historical context for the ruins you're seeing.

Naples: National Archaeological Museum

Italy's most prestigious archaeological museum can be found in Naples. Chow down on some famous Neapolitan pizza before you arrive; you'll need the sustenance to explore the museum's vast and fascinating holdings. The museum is built upon the Farnese Collection, which was moved there in 1777 from what was the Royal Bourbon Museum. Visiting the museum is the perfect complement to visiting the nearby archaeological ruins of Pompeii or Herculaneum, where everyday items and symbolic pieces like sculptures from those ruins are housed. They include glassware, mosaics, frescoes, jewelry, coins, sculptures (like the famous Doriforo). The Egyptian collection was curated in 1920s from collectors like Cardinal Borgia. There are even exhibits dating back to the Paleolithic Era. Tip: The museum's secret room is reserved for adults only, as it houses examples of Roman-era erotica, as well as sexually explicit finds from Pompeii. The room opened in the mid-19th century but was then closed for a century or so, due to controversy.

Naples: Pompeii In the year 79 AD, the city of Pompeii, home to 20,000 people, was a vibrant and booming center of trade. All of that changed in a matter of minutes when a massive eruption by nearby volcano Mount Vesuvius covered the city and its inhabitants in three feet of mud and ash. Now Pompeii is a thriving Roman city frozen in time and offers one of the best examples of what daily life was like during Roman empire. For more than 250 years, tourists have been walking down the preserved streets of Pompeii and peeking into fresco-laden buildings. However, the most startling site at Pompeii is that of the ash-encased bodies reflecting the exact moments when life was transformed forever.

Tip: If your ship is in port overnight, look into Pompeii's special nighttime tours during the summer.

Palermo: Palazzo dei Normanni/Cappella Palatina

Palermo is home to Italy's second-most famous (after the Sistine Chapel at the Vatican) chapel, the Cappella Palatina. About half the size of the Sistine Chapel, this 12th-century chapel in the city's royal palace (Palazzo dei Normanni) is filled with brilliant mosaics depicting the lives of the saints, in particular St. Paul and St. Peter, to whom the chapel is dedicated. Byzantine mosaics of this quality can only be seen elsewhere in Istanbul or Ravenna in northern Italy. If you can tear your eyes away from the sparkle and shine of the mosaics, you'll be mesmerized by the colorful cosmati flooring with geometric inlay at your feet. The facets of the chapel -- Byzantine mosaics, Norman architecture, Arab arches -- reflect the many cultures that have influenced both Palermo and Sicily.

Tip: Palermo is the place to taste the world's best cannoli (fried pastry dough filled with a sweetened ricotta).