Piraeus is the gateway to Athens , which, in turn, is rightfully considered the center of the centers of the whole world, with the main attraction - the acropolis. Piraeus is an old port city serving the port of Athens, the largest port in Greece to date. Piraeus is part of the great Athens, which boasts an abundance of attractions, including unique monuments of national fine art. More than two hundred museums and galleries, including the University History Museum, the Ceramics Archaeological Museum and many others, will hospitably welcome you within their walls and familiarize themselves with the culture of this area.

Santorini, classically Thera, and officially Thira, is an island in the southern Aegean Sea, about 200 km (120 mi) southeast of Greece's mainland. It is the largest island of a small, circular archipelago, which bears the same name and is the remnant of a volcanic caldera. It forms the southernmost member of the Cyclades group of islands, with an area of approximately 73 km2 (28 sq mi) and a 2011 census population of 15,550. The municipality of Santorini includes the inhabited islands of Santorini and Therasia and the uninhabited islands of Nea Kameni, Palaia Kameni, Aspronisi, and Christiana. The total land area is 90.623 km2 (34.990 sq mi).Santorini is part of the Thira regional unit.

The island was the site of one of the largest volcanic eruptions in recorded history: the Minoan eruption(sometimes called the Thera eruption), which occurred about 3,600 years ago at the height of the Minoan civilization. The eruption left a large caldera surrounded by volcanic ash deposits hundreds of metres deep. It may have led indirectly to the collapse of the Minoan civilization on the island of Crete, 110 km (68 mi) to the south, through a gigantic tsunami. Another popular theory holds that the Thera eruption is the source of the legend of Atlantis.

It is the most active volcanic centre in the South Aegean Volcanic Arc, though what remains today is chiefly a water-filled caldera. The volcanic arc is approximately 500 km (310 mi) long and 20 to 40 km (12 to 25 mi) wide. The region first became volcanically active around 3–4 million years ago[citation needed], though volcanism on Thera began around 2 million years ago with the extrusion of dacitic lavas from vents around the Akrotiri.

Mykonos is a Greek island, part of the Cyclades, lying between Tinos, Syros, Paros and Naxos. The island spans an area of 85.5 square kilometres (33.0 sq mi) and rises to an elevation of 341 metres (1,119 feet) at its highest point. There are 10,134 inhabitants (2011 census), most of whom live in the largest town, Mykonos, which lies on the west coast. The town is also known as Chora (i.e. the Town in Greek, following the common practice in Greece when the name of the island itself is the same as the name of the principal town).

Rome is the capital city and a special comune of Italy (named Comune di Roma Capitale). Rome also serves as the capital of the Lazio region. With 2,872,800 residents in 1,285 km2(496.1 sq mi), it is also the country's most populated comune. It is the fourth-most populous city in the European Union by population within city limits. It is the centre of the Metropolitan City of Rome, which has a population of 4,355,725 residents, thus making it the most populous metropolitan city in Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of the Tiber. The Vatican City (the smallest country in the world) is an independent country inside the city boundaries of Rome, the only existing example of a country within a city: for this reason Rome has been often defined as capital of two states.

Rome's history spans 28 centuries. While Roman mythology dates the founding of Rome at around 753 BC, the site has been inhabited for much longer, making it one of the oldest continuously occupied sites in Europe. The city's early population originated from a mix of Latins, Etruscans, and Sabines. Eventually, the city successively became the capital of the Roman Kingdom, the Roman Republic and the Roman Empire, and is regarded as the birthplace of Western civilization and by some as the first ever metropolis. It was first called The Eternal City (Latin: Urbs Aeterna; Italian: La Città Eterna) by the Roman poet Tibullus in the 1st century BC, and the expression was also taken up by Ovid, Virgil, and Livy. Rome is also called the "Caput Mundi" (Capital of the World). After the fall of the Western Empire, which marked the beginning of the Middle Ages, Rome slowly fell under the political control of the Papacy, which had settled in the city since the 1st century AD, until in the 8th century it became the capital of the Papal States, which lasted until 1870. Beginning with the Renaissance, almost all the popes since Nicholas V (1447–1455) pursued over four hundred years a coherent architectural and urban programme aimed at making the city the artistic and cultural centre of the world. In this way, Rome became first one of the major centres of the Italian Renaissance, and then the birthplace of both the Baroque style and Neoclassicism. Famous artists, painters, sculptors and architects made Rome the centre of their activity, creating masterpieces throughout the city. In 1871, Rome became the capital of the Kingdom of Italy, which, in 1946, became the Italian Republic.

Rome has the status of a global city. In 2016, Rome ranked as the 14th-most-visited city in the world, 3rd most visited in the European Union, and the most popular tourist attraction in Italy. Its historic centre is listed by UNESCO as a World Heritage Site. The famous Vatican Museums are among the world's most visited museums while the Colosseum was the most popular tourist attraction in world with 7.4 million visitors in 2018. Host city for the 1960 Summer Olympics, Rome is the seat of several specialized agencies of the United Nations, such as the Food and Agriculture Organization (FAO), the World Food Programme (WFP) and the International Fund for Agricultural Development (IFAD). The city also hosts the Secretariat of the Parliamentary Assembly of the Union for the Mediterranean (UfM) as well as the headquarters of many international business companies such as Eni, Enel, TIM, Leonardo S.p.A., and national and international banks such as Unicredit and BNL. Its business district, called EUR, is the base of many companies involved in the oil industry, the pharmaceutical industry, and financial services. Rome is also an important fashion and design centre thanks to renowned international brands centered in the city. Rome's Cinecittà Studios have been the set of many Academy Award–winning movies.

Mallorca is the largest island in the Balearic Islands, which are part of Spain and located in the Mediterranean. The native language, as on the rest of the Balearic Islands, is Catalan, which is co-official with Spanish.

The capital of the island, Palma, is also the capital of the autonomous community of the Balearic Islands. The Balearic Islands have been an autonomous region of Spain since 1983. There are two small islands off the coast of Mallorca: Cabrera (southeast of Palma) and Dragonera (west of Palma). The anthem of Mallorca is "La Balanguera".

Like the other Balearic Islands of Menorca, Ibiza and Formentera, the island is an extremely popular holiday destination, particularly for tourists from Germany and the United Kingdom. The international airport, Palma de Mallorca Airport, is one of the busiest in Spain; it was used by 28.0 million passengers in 2017, increasing every year since 2012.

The name derives from Classical Latin insula maior, "larger island". Later, in Medieval Latin, this became Maiorica, "the larger one", in comparison to Menorca, "the smaller one".

 Barcelona is a city in Spain. It is the capital and largest city of Catalonia, as well as the second most populous municipality of Spain. With a population of 1.6 million within city limits, its urban area extends to numerous neighbouring municipalities within the Province of Barcelona and is home to around 4.8 million people, making it the sixth most populous urban area in the European Union after Paris, London, Madrid, the Ruhr area and Milan. It is one of the largest metropolises on the Mediterranean Sea, located on the coast between the mouths of the rivers Llobregat and Besòs, and bounded to the west by the Serra de Collserola mountain range, the tallest peak of which is 512 metres (1,680 feet) high.

Founded as a Roman city, in the Middle Ages Barcelona became the capital of the County of Barcelona. After merging with the Kingdom of Aragon, Barcelona continued to be an important city in the Crown of Aragon as an economic and administrative centre of this Crown and the capital of the Principality of Catalonia. Barcelona has a rich cultural heritage and is today an important cultural centre and a major tourist destination. Particularly renowned are the architectural works of Antoni Gaudí and Lluís Domènech i Montaner, which have been designated UNESCO World Heritage Sites. The headquarters of the Union for the Mediterranean are located in Barcelona. The city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments.

Barcelona is one of the world's leading tourist, economic, trade fair and cultural centres, and its influence in commerce, education, entertainment, media, fashion, science, and the arts all contribute to its status as one of the world's major global cities. It is a major cultural and economic centre in southwestern Europe, 24th in the world (before Zürich, after Frankfurt) and a financial centre. In 2008 it was the fourth most economically powerful city by GDP in the European Union and 35th in the world with GDP amounting to €177 billion. In 2012 Barcelona had a GDP of $170 billion; and it was leading Spain in employment rate in that moment.

In 2009 the city was ranked Europe's third and one of the world's most successful as a city brand. In the same year the city was ranked Europe's fourth best city for business and fastest improving European city, with growth improved by 17% per year, and the city has been experiencing strong and renewed growth for the past three years. Since 2011 Barcelona has been a leading smart city in Europe. Barcelona is a transport hub, with the Port of Barcelona being one of Europe's principal seaports and busiest European passenger port, an international airport, Barcelona–El Prat Airport, which handles over 50 million passengers per year, an extensive motorway network, and a high-speed rail line with a link to France and the rest of Europe.