Southampton is the largest city in the ceremonial county of Hampshire, England. It is 69 miles (111 km) south-west of London and 15 miles (24 km) west north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest. It lies at the northernmost point of Southampton Water at the confluence of the Rivers Test and Itchen, with the River Hamble joining to the south of the urban area. The city, which is a unitary authority, has an estimated population of 253,651. The city's name is sometimes abbreviated in writing to "So'ton" or "Soton", and a resident of Southampton is called a Sotonian.

Significant employers in the city include Southampton City Council, the University of Southampton, Solent University, Southampton Airport, Ordnance Survey, BBC South, the NHS, ABP and Carnival UK. Southampton is noted for its association with the RMS Titanic, the Spitfire and more generally in the World War II narrative as one of the departure points for D-Day, and more recently as the home port of a number of the largest cruise ships in the world. Southampton has a large shopping centre and retail park, Westquay. In 2014, the city council approved a neighbouring followup Westquay South which opened in 2016–2017.

In the 2001 census Southampton and Portsmouth were recorded as being parts of separate urban areas; however by the time of the 2011 census they had merged apolitically to become the sixth-largest built-up area in England with a population of 855,569. This built-up area is part of the metropolitan area known as South Hampshire, which is also known as Solent City, particularly in the media when discussing local governance organisational changes. With a population of over 1.5 million this makes the region one of the United Kingdom's most populous metropolitan areas.

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.

 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.

Lisbon is the capital and the largest city of Portugal, with an estimated population of 505,526 within its administrative limits in an area of 100.05 km2. Its urban area extends beyond the city's administrative limits with a population of around 2.8 million people, being the 11th-most populous urban area in the European Union. About 3 million people live in the Lisbon Metropolitan Area (which represents approximately 27% of the country's population). It is mainland Europe's westernmost capital city and the only one along the Atlantic coast. Lisbon lies in the western Iberian Peninsula on the Atlantic Ocean and the River Tagus. The westernmost areas of its metro area form the westernmost point of Continental Europe, which is known as Cabo da Roca, located in the Sintra Mountains.

Vigo is a city and municipality adjoining the Atlantic Ocean in the province of Pontevedra in Galicia, northwest Spain. It is the capital of the comarca of Vigo and Vigo metropolitan area.

Vigo is the most populous municipality of Galicia, the 14th in Spain, and the most populous Spanish municipality that is not the capital of a province. It has an area of 109.06 km2 (42.11 sq mi) and had a population of 292,817 in 2016.

The city is located in the southwest of Galicia, in the southern part of Vigo Ria, one of Europe's rainiest areas. In the northeast, it borders the municipality of Redondela; in the east, Mos; in the south, O Porriño and Gondomar; and in the southwest, Nigrán. On the other side of its bay are the municipalities of Cangas and Moaña. They are all part of the southern Galician region called Rías Baixas. Vigo is just north of the border with Portugal; its nearest larger city is Porto, Portugal's second-largest city.

Vigo and its metropolitan area are one of the region's primary economic agents.

Southampton is the largest city in the ceremonial county of Hampshire, England. It is 69 miles (111 km) south-west of London and 15 miles (24 km) west north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest. It lies at the northernmost point of Southampton Water at the confluence of the Rivers Test and Itchen, with the River Hamble joining to the south of the urban area. The city, which is a unitary authority, has an estimated population of 253,651. The city's name is sometimes abbreviated in writing to "So'ton" or "Soton", and a resident of Southampton is called a Sotonian.

Significant employers in the city include Southampton City Council, the University of Southampton, Solent University, Southampton Airport, Ordnance Survey, BBC South, the NHS, ABP and Carnival UK. Southampton is noted for its association with the RMS Titanic, the Spitfire and more generally in the World War II narrative as one of the departure points for D-Day, and more recently as the home port of a number of the largest cruise ships in the world. Southampton has a large shopping centre and retail park, Westquay. In 2014, the city council approved a neighbouring followup Westquay South which opened in 2016–2017.

In the 2001 census Southampton and Portsmouth were recorded as being parts of separate urban areas; however by the time of the 2011 census they had merged apolitically to become the sixth-largest built-up area in England with a population of 855,569. This built-up area is part of the metropolitan area known as South Hampshire, which is also known as Solent City, particularly in the media when discussing local governance organisational changes. With a population of over 1.5 million this makes the region one of the United Kingdom's most populous metropolitan areas.