Early travelers described Rhodes as a town of two parts: a castle or high town (Collachium) and a lower city. Today Rhodes town—sometimes referred to as Ródos town—is still a city of two parts: the Old Town, a UNESCO World Heritage site that incorporates the high town and lower city, and the modern metropolis, or New Town, spreading away from the walls that encircle the Old Town. The narrow streets of the Old Town are for the most part closed to cars and are lined with Orthodox and Catholic churches, Turkish houses (some of which follow the ancient orthogonal plan), and medieval public buildings with exterior staircases and facades elegantly constructed of well-cut limestone from Lindos. Careful reconstruction in recent years has enhanced the harmonious effect.

Although the fishing boats still go out in good weather, Mykonos largely makes its living from tourism these days. The summer crowds have turned one of the poorest islands in Greece into one of the richest. Old Mykonians complain that their young, who have inherited stores where their grandfathers once sold eggs or wine, get so much rent that they have lost ambition, and in summer sit around pool bars at night with their friends, and hang out in Athens in winter when island life is less scintillating. Put firmly on the map by Jackie O in the 1960s, Mykonos town—called Hora by the locals—remains the Saint-Tropez of the Greek islands. The scenery is memorable, with its whitewashed streets, Little Venice, the Kato Myli ridge of windmills, and Kastro, the town's medieval quarter. Its cubical two- or three-story houses and churches, with their red or blue doors and domes and wooden balconies, have been long celebrated as some of the best examples of classic Cycladic architecture. Luckily, the Greek Archaeological Service decided to preserve the town, even when the Mykonians would have preferred to rebuild, and so the Old Town has been impressively preserved. Pink oleander, scarlet hibiscus, and trailing green pepper trees form a contrast amid the dazzling whiteness, whose frequent renewal with whitewash is required by law. Any visitor who has the pleasure of getting lost in its narrow streets (made all the narrower by the many outdoor stone staircases, which maximize housing space in the crowded village) will appreciate how its confusing layout was designed to foil pirates—if it was designed at all. After Mykonos fell under Turkish rule in 1537, the Ottomans allowed the islanders to arm their vessels against pirates, which had a contradictory effect: many of them found that raiding other islands was more profitable than tilling arid land. At the height of Aegean piracy, Mykonos was the principal headquarters of the corsair fleets—the place where pirates met their fellows, found willing women, and filled out their crews. Eventually the illicit activity evolved into a legitimate and thriving trade network. Morning on Mykonos town's main quay is busy with deliveries, visitors for the Delos boats, lazy breakfasters, and street cleaners dealing with the previous night's mess. In late morning the cruise-boat people arrive, and the shops are all open. In early afternoon, shaded outdoor tavernas are full of diners eating salads (Mykonos's produce is mostly imported); music is absent or kept low. In mid- and late afternoon, the town feels sleepy, since so many people are at the beach, on excursions, or sleeping in their air-conditioned rooms; even some tourist shops close for siesta. By sunset, people have come back from the beach, having taken their showers and rested. At night, the atmosphere in Mykonos ramps up. The cruise-boat people are mostly gone, coughing three-wheelers make no deliveries in the narrow streets, and everyone is dressed sexy for summer and starting to shimmy with the scene. Many shops stay open past midnight, the restaurants fill up, and the bars and discos make ice cubes as fast as they can. Ready to dive in? Begin your tour of Mykonos town (Hora) by starting out at its heart: Mando Mavrogenous Square.

Undoubtedly the most extraordinary island in the Aegean, crescent-shape Santorini remains a mandatory stop on the Cycladic tourist route—even if it's necessary to enjoy the sensational sunsets from Ia, the fascinating excavations, and the dazzling white towns with a million other travelers. Called Kállisti (the "Loveliest") when first settled, the island has now reverted to its subsequent name of Thira, after the 9th-century-BC Dorian colonizer Thiras. The place is better known, however, these days as Santorini, a name derived from its patroness, St. Irene of Thessaloniki, the Byzantine empress who restored icons to Orthodoxy and died in 802. You can fly conveniently to Santorini, but to enjoy a true Santorini rite of passage, opt instead for the boat trip here, which provides a spectacular introduction. After the boat sails between Sikinos and Ios, your deck-side perch approaches two close islands with a passage between them. The bigger one on the left is Santorini, and the smaller on the right is Thirassia. Passing between them, you see the village of Ia adorning Santorini's northernmost cliff like a white geometric beehive. You are in the caldera (volcanic crater), one of the world's truly breathtaking sights: a demilune of cliffs rising 1,100 feet, with the white clusters of the towns of Fira and Ia perched along the top. The bay, once the high center of the island, is 1,300 feet in some places, so deep that when boats dock in Santorini's shabby little port of Athinios, they do not drop anchor. The encircling cliffs are the ancient rim of a still-active volcano, and you are sailing east across its flooded caldera. On your right are the Burnt isles, the White isle, and other volcanic remnants, all lined up as if some outsize display in a geology museum. Hephaestus's subterranean fires smolder still—the volcano erupted in 198 BC, about 735, and there was an earthquake in 1956. Indeed, Santorini and its four neighboring islets are the fragmentary remains of a larger landmass that exploded about 1600 BC: the volcano's core blew sky high, and the sea rushed into the abyss to create the great bay, which measures 10 km by 7 km (6 mi by 4½ mi) and is 1,292 feet deep. The other pieces of the rim, which broke off in later eruptions, are Thirassia, where a few hundred people live, and deserted little Aspronissi ("White isle"). In the center of the bay, black and uninhabited, two cones, the Burnt Isles of Palea Kameni and Nea Kameni, appeared between 1573 and 1925. There has been too much speculation about the identification of Santorini with the mythical Atlantis, mentioned in Egyptian papyri and by Plato (who says it's in the Atlantic), but myths are hard to pin down. This is not true of old arguments about whether tidal waves from Santorini's cataclysmic explosion destroyed Minoan civilization on Crete, 113 km (70 mi) away. The latest carbon-dating evidence, which points to a few years before 1600 BC for the eruption, clearly indicates that the Minoans outlasted the eruption by a couple of hundred years, but most probably in a weakened state. In fact, the island still endures hardships: since antiquity, Santorini has depended on rain collected in cisterns for drinking and irrigating—the well water is often brackish—and the serious shortage is alleviated by the importation of water. However, the volcanic soil also yields riches: small, intense tomatoes with tough skins used for tomato paste (good restaurants here serve them); the famous Santorini fava beans, which have a light, fresh taste; barley; wheat; and white-skin eggplants.

Split's ancient core is so spectacular and unusual that a visit is more than worth your time. The heart of the city lies within the walls of Roman emperor Diocletian's retirement palace, which was built in the 3rd century AD. Diocletian, born in the nearby Roman settlement of Salona in AD 245, achieved a brilliant career as a soldier and became emperor at the age of 40. In 295 he ordered this vast palace to be built in his native Dalmatia, and when it was completed he stepped down from the throne and retired to his beloved homeland. Upon his death, he was laid to rest in an octagonal mausoleum, around which Split's magnificent cathedral was built.In 615, when Salona was sacked by barbarian tribes, those fortunate enough to escape found refuge within the stout palace walls and divided up the vast imperial apartments into more modest living quarters. Thus, the palace developed into an urban center, and by the 11th century the settlement had expanded beyond the ancient walls.Under the rule of Venice (1420–1797), Split—as a gateway to the Balkan interior—became one of the Adriatic's main trading ports, and the city's splendid Renaissance palaces bear witness to the affluence of those times. When the Habsburgs took control during the 19th century, an overland connection to Central Europe was established by the construction of the Split–Zagreb–Vienna railway line.After World War II, the Tito years saw a period of rapid urban expansion: industrialization accelerated and the suburbs extended to accommodate high-rise apartment blocks. Today the historic center of Split is included on UNESCO's list of World Heritage Sites.

Dalmatia's capital for more than 1,000 years, Zadar is all too often passed over by travelers on their way to Split or Dubrovnik. What they miss out on is a city of more than 73,000 that is remarkably lovely and lively despite—and, in some measure, because of—its tumultuous history. The Old Town, separated from the rest of the city on a peninsula some 4 km (2½ miles) long and just 1,640 feet wide, is bustling and beautiful: the marble pedestrian streets are replete with Roman ruins, medieval churches, palaces, museums, archives, and libraries. Parts of the new town are comparatively dreary, a testament to what a world war followed by decades of communism, not to mention a civil war, can do to the architecture of a city that is 3,000 years old. A settlement had already existed on the site of the present-day city for some 2,000 years when Rome finally conquered Zadar in the 1st century BC; the foundations of the forum can be seen today. Before the Romans came the Liburnians had made it a key center for trade with the Greeks and Romans for 800 years. In the 3rd century BC the Romans began to seriously pester the Liburnians, but required two centuries to bring the area under their control. During the Byzantine era, Zadar became the capital of Dalmatia, and this period saw the construction of its most famous church, the 9th-century St. Donat's Basilica. It remained the region's foremost city through the ensuing centuries. The city then experienced successive onslaughts and occupations—both long and short—by the Osogoths, the Croatian-Hungarian kings, the Venetians, the Turks, the Habsburgs, the French, the Habsburgs again, and finally the Italians before becoming part of Yugoslavia and, in 1991, the independent republic of Croatia. Zadar was for centuries an Italian-speaking city, and Italian is still spoken widely, especially by older people. Indeed, it was ceded to Italy in 1921 under the Treaty of Rapallo (and reverted to its Italian name of Zara). Its occupation by the Germans from 1943 led to intense bombing by the Allies during World War II, which left most of the city in ruins. Zadar became part of Tito's Yugoslavia in 1947, prompting many Italian residents to leave. Zadar's most recent ravages occurred during a three-month siege by Serb forces and months more of bombardment during the Croatian-Serbian war between 1991 and 1995. But you'd be hard-pressed to find outward signs of this today in what is a city to behold. There are helpful interpretive signs in English all around the Old Town, so you certainly won't feel lost when trying to make sense of the wide variety of architectural sites you might otherwise pass by with only a cursory look.

A small, quiet, well-heeled city, Ravenna has brick palaces, cobblestone streets, magnificent monuments, and spectacular Byzantine mosaics. The high point in its civic history occurred in the 5th century, when Pope Honorious moved his court here from Rome. Gothic kings Odoacer and Theodoric ruled the city until it was conquered by the Byzantines in AD 540. Ravenna later fell under the sway of Venice, and then, inevitably, the Papal States.Because Ravenna spent much of its past looking east, its greatest art treasures show that Byzantine influence. Churches and tombs with the most unassuming exteriors contain within them walls covered with sumptuous mosaics. These beautifully preserved Byzantine mosaics put great emphasis on nature, which you can see in the delicate rendering of sky, earth, and animals. Outside Ravenna, the town of Classe hides even more mosaic gems.