Miami, officially the City of Miami, is the cultural, economic and financial center of South Florida. Miami is the seat of Miami-Dade County, the most populous county in Florida. The city covers an area of about 56.6 square miles (147 km2), between the Everglades to the west and Biscayne Bay on the east; with a 2017 estimated population of 463,347, Miami is the sixth most densely populated major city in the United States. The Miami metropolitan area is home to 6.1 million people and the seventh-largest metropolitan area in the nation. Miami's metro area is the second-most populous metropolis in the southeastern United States and fourth-largest urban area in the U.S.

Miami is a major center, and a leader in finance, commerce, culture, media, entertainment, the arts, and international trade. The Miami Metropolitan Area is by far the largest urban economy in Florida and the 12th largest in the United States with a GDP of $344.9 billion as of 2017. In 2012, Miami was classified as an "Alpha−" level world city in the World Cities Study Group's inventory. In 2010, Miami ranked seventh in the United States and 33rd among global cities in terms of business activity, human capital, information exchange, cultural experience, and political engagement. In 2008, Forbes magazine ranked Miami "America's Cleanest City", for its year-round good air quality, vast green spaces, clean drinking water, clean streets, and citywide recycling programs. According to a 2009 UBS study of 73 world cities, Miami was ranked as the richest city in the United States, and the world's seventh-richest city in terms of purchasing power. Miami is nicknamed the "Capital of Latin America" and is the largest city with a Cuban-American plurality.

Greater Downtown Miami has one of the largest concentrations of international banks in the United States, and is home to many large national and international companies. The Civic Center is a major center for hospitals, research institutes, medical centers, and biotechnology industries. For more than two decades, the Port of Miami, known as the "Cruise Capital of the World", has been the number one cruise passenger port in the world. It accommodates some of the world's largest cruise ships and operations, and is the busiest port in both passenger traffic and cruise lines. Metropolitan Miami is also a major tourism hub in the southeastern U.S. for international visitors, ranking number two in the country after New York City.

Madeira, officially the Autonomous Region of Madeira, is one of the two autonomous regions of Portugal (along with the Azores). It is an archipelago situated in the north Atlantic Ocean, southwest of Portugal. Its total population was estimated in 2011 at 267,785. The capital of Madeira is Funchal, which is located on the main island's south coast.

The archipelago is just under 400 kilometres (250 mi) north of Tenerife, Canary Islands. Bermuda and Madeira, a few time zones apart, are the only land in the Atlantic on the 32nd parallel north. It includes the islands of Madeira, Porto Santo, and the Desertas, administered together with the separate archipelago of the Savage Islands. The region has political and administrative autonomy through the Administrative Political Statue of the Autonomous Region of Madeiraprovided for in the Portuguese Constitution. The autonomous region is an integral part of the European Union as an outermost region.

Gibraltar  is a British Overseas Territory located at the southern tip of the Iberian Peninsula. It has an area of 6.7 km2 (2.6 sq mi) and is bordered to the north by Spain. The landscape is dominated by the Rock of Gibraltar at the foot of which is a densely populated town area, home to over 30,000 people, primarily Gibraltarians. It shares a maritime border with Morocco.

In 1704, Anglo-Dutch forces captured Gibraltar from Spain during the War of the Spanish Succession on behalf of the Habsburg claim to the Spanish throne. The territory was ceded to Great Britain in perpetuity under the Treaty of Utrechtin 1713. During World War II it was an important base for the Royal Navy as it controlled the entrance and exit to the Mediterranean Sea, which is only 8 miles (13 km) wide at this naval choke point. It remains strategically important, with half the world's seaborne trade passing through the strait. Today Gibraltar's economy is based largely on tourism, online gambling, financial services and cargo ship refuelling.

The sovereignty of Gibraltar is a point of contention in Anglo-Spanish relations because Spain asserts a claim to the territory. Gibraltarians rejected proposals for Spanish sovereignty in a 1967 referendum and, in a 2002 referendum, the idea of shared sovereignty was also rejected.

The city of Cartagena, known in the colonial era as Cartagena de Indias, is a major port founded in 1533, located on the northern coast of Colombia in the Caribbean Coast Region. It was strategically located between the Magdalena and Sinú rivers and became the main port for trade between Spain and its overseas empire, establishing its importance by the early 1540s. During the colonial era it was a key port for the export of Peruvian silver to Spain and for the import of enslaved Africans under the asiento system. It was defensible against pirate attacks in the Caribbean. It is the capital of the Bolívar Department, and had a population 971,592 as of 2016. It is the fifth-largest city in Colombia and the second largest in the region, after Barranquilla. The urban area of Cartagena is also the fifth-largest urban area in the country. Economic activities include the maritime and petrochemicals industries, as well as tourism.

The city was founded on June 1, 1533, and named after Cartagena, Spain, settlement in the region around Cartagena Bay by various indigenous people dates back to 4000 BC. During the Spanish colonial period Cartagena served a key role in administration and expansion of the Spanish empire. It was a center of political, ecclesiastical, and economic activity. In 1984, Cartagena's colonial walled city and fortress were designated a UNESCO World Heritage Site.

 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.