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.

Le Havre is a port city located in the northwest of France, on the coast of the English Channel. It is an important center of maritime trade and shipbuilding. Founded in the 16th century, Le Havre quickly developed thanks to its strategic location, becoming one of the largest ports in the country. The city is known for its modern architecture, carefully planned after the destructions of World War II. In 2005, the historic center of the city was included in the UNESCO World Heritage list, and the famous architectural ensemble designed by Auguste Perret became an essential part of the city's identity.

Today, Le Havre attracts tourists with its unique atmosphere, blending old and new elements. One of its main attractions is the Notre-Dame-de-Grâce, as well as the Dunkirk Cultural Center, which hosts concerts, exhibitions, and theatrical performances. The local beaches and promenades are perfect places for walks and relaxation, while numerous restaurants offer fresh seafood dishes. Le Havre has also become an important cultural and economic center, welcoming guests not only from France but also from all over the world.

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.