Italy

The infinite variety of street life, the nooks and crannies of the medieval Barri Gòtic, the ceramic tile and stained glass of Art Nouveau facades, the art and music, the throb of street life, the food (ah, the food!)—one way or another, Barcelona will find a way to get your full attention. The capital of Catalonia is a banquet for the senses, with its beguiling mix of ancient and modern architecture, tempting cafés and markets, and sun-drenched Mediterranean beaches. A stroll along La Rambla and through waterfront Barceloneta, as well as a tour of Gaudí's majestic Sagrada Famíliaand his other unique creations, are part of a visit to Spain's second-largest city. Modern art museums and chic shops call for attention, too. Barcelona's vibe stays lively well into the night, when you can linger over regional wine and cuisine at buzzing tapas bars.

It's no wonder that all roads lead to the fascinating and maddening metropolis of Athens. Lift your eyes 200 feet above the city to the Parthenon, its honey-color marble columns rising from a massive limestone base, and you behold architectural perfection that has not been surpassed in 2,500 years. But, today, this shrine of classical form dominates a 21st-century boomtown. To experience Athens—Athína in Greek—fully is to understand the essence of Greece: ancient monuments surviving in a sea of cement, startling beauty amid the squalor, tradition juxtaposed with modernity. Locals depend on humor and flexibility to deal with the chaos; you should do the same. The rewards are immense. Although Athens covers a huge area, the major landmarks of the ancient Greek, Roman, and Byzantine periods are close to the modern city center. You can easily walk from the Acropolis to many other key sites, taking time to browse in shops and relax in cafés and tavernas along the way. From many quarters of the city you can glimpse "the glory that was Greece" in the form of the Acropolis looming above the horizon, but only by actually climbing that rocky precipice can you feel the impact of the ancient settlement. The Acropolis and Filopappou, two craggy hills sitting side by side; the ancient Agora (marketplace); and Kerameikos, the first cemetery, form the core of ancient and Roman Athens. Along the Unification of Archaeological Sites promenade, you can follow stone-paved, tree-lined walkways from site to site, undisturbed by traffic. Cars have also been banned or reduced in other streets in the historical center. In the National Archaeological Museum, vast numbers of artifacts illustrate the many millennia of Greek civilization; smaller museums such as the Goulandris Museum of Cycladic Art Museum and the Byzantine and Christian Museum illuminate the history of particular regions or periods. Athens may seem like one huge city, but it is really a conglomeration of neighborhoods with distinctive characters. The Eastern influences that prevailed during the 400-year rule of the Ottoman Empire are still evident in Monastiraki, the bazaar area near the foot of the Acropolis. On the northern slope of the Acropolis, stroll through Plaka (if possible by moonlight), an area of tranquil streets lined with renovated mansions, to get the flavor of the 19th-century's gracious lifestyle. The narrow lanes of Anafiotika, a section of Plaka, thread past tiny churches and small, color-washed houses with wooden upper stories, recalling a Cycladic island village. In this maze of winding streets, vestiges of the older city are everywhere: crumbling stairways lined with festive tavernas; dank cellars filled with wine vats; occasionally a court or diminutive garden, enclosed within high walls and filled with magnolia trees and the flaming trumpet-shaped flowers of hibiscus bushes. Formerly run-down old quarters, such as Thission, Gazi and Psirri, popular nightlife areas filled with bars and mezedopoleia (similar to tapas bars), are now in the process of gentrification, although they still retain much of their original charm, as does the colorful produce and meat market on Athinas. The area around Syntagma Square, the tourist hub, and Omonia Square, the commercial heart of the city about 1 km (½ mi) northwest, is distinctly European, having been designed by the court architects of King Otho, a Bavarian, in the 19th century. The chic shops and bistros of ritzy Kolonaki nestle at the foot of Mt. Lycabettus, Athens's highest hill (909 feet). Each of Athens's outlying suburbs has a distinctive character: in the north is wealthy, tree-lined Kifissia, once a summer resort for aristocratic Athenians, and in the south and southeast lie Glyfada, Voula, and Vouliagmeni, with their sandy beaches, seaside bars, and lively summer nightlife. Just beyond the city's southern fringes is Piraeus, a bustling port city of waterside fish tavernas and Saronic Gulf views.

The only city in the world that can lay claim to straddling two continents, Istanbul—once known as Constantinople, capital of the Byzantine and then the Ottoman Empire—has for centuries been a bustling metropolis with one foot in Europe and the other in Asia. Istanbul embraces this enviable position with both a certain chaos and inventiveness, ever evolving as one of the world’s most cosmopolitan crossroads. It’s often said that Istanbul is the meeting point of East and West, but visitors to this city built over the former capital of two great empires are likely to be just as impressed by the juxtaposition of old and new. Office towers creep up behind historic palaces, women in chic designer outfits pass others wearing long skirts and head coverings, peddlers’ pushcarts vie with battered old Fiats and shiny BMWs for dominance of the noisy, narrow streets, and the Grand Bazaar competes with modern shopping malls. At dawn, when the muezzin's call to prayer resounds from ancient minarets, there are inevitably a few hearty revelers still making their way home from nightclubs and bars. Most visitors to this sprawling city of more than 14 million will first set foot in the relatively compact Old City, where the legacy of the Byzantine and Ottoman empires can be seen in monumental works of architecture like the brilliant Aya Sofya and the beautifully proportioned mosques built by the great architect Sinan. Though it would be easy to spend days, if not weeks, exploring the wealth of attractions in the historical peninsula, visitors should make sure also to venture elsewhere in order to experience the vibrancy of contemporary Istanbul. With a lively nightlife propelled by its young population and an exciting arts scene that’s increasingly on the international radar—thanks in part to its stint as the European Capital of Culture in 2010—Istanbul is truly a city that never sleeps. It’s also a place where visitors will feel welcome: Istanbul may be on the Bosphorus, but at heart it’s a Mediterranean city, whose friendly inhabitants are effusively social and eager to share what they love most about it.