Barcelona is a city on the northeastern coast of Spain. It is the capital and largest city of the autonomous community of Catalonia, as well as the second-most populous municipality of Spain after Madrid. With a population of 1.7 million within city limits, its urban area extends to numerous neighbouring municipalities within the province of Barcelona and is home to around 5.7 million people, making it the fifth most populous urban area of the European Union after Paris, the Ruhr area, Madrid, 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.
Basseterre is the capital and largest city of Saint Kitts and Nevis with an estimated population of 14,000 in 2018. Geographically, the Basseterre port is located at 17°18′N 62°44′W, on the south-western coast of Saint Kitts Island, and it is one of the chief commercial depots of the Leeward Islands. The city lies within Saint George Basseterre Parish.
Belfast is the capital city and main port of Northern Ireland. It stands on the banks of the river Lagan, and is connected to the open sea through Belfast Lough and the North Channel. The city is the largest in Northern Ireland and the second-largest, after Dublin, in Ireland, with a recorded population in 2021 of 345,418 and of 704,406 for the greater metropolitan area.
Bilbao or Bilbo is a city in northern Spain, the largest city in the province of Biscay and in the autonomous community of the Basque Country. With a population of 347,342 as of 2024, it is the 11th most populous city in Spain, and the most populous in northern Spain. The Bilbao metropolitan area has 1,037,847 inhabitants, making it the most populous metropolitan area in northern Spain. The comarca of Greater Bilbao is the fifth-largest urban area in Spain. Bilbao is also the main urban area in what is defined as the Greater Basque region.
Boston is the capital and most populous city of the U.S. state of Massachusetts. It serves as a cultural and financial center of New England, a region of the Northeastern United States. Boston has an area of 48.4 square miles (125 km2) and a population of 675,647 as of the 2020 census, making it the third-most populous city in the Northeastern United States after New York City and Philadelphia. The larger Greater Boston metropolitan statistical area had a population of 5 million in 2025, making it the largest metropolis in New England and the eleventh-largest in the United States.
Brest is a port city in the Finistère department, Brittany. Located in a sheltered bay not far from the western tip of a peninsula and the western extremity of metropolitan France, Brest is an important harbour and the second largest French military port after Toulon. The city is located on the western edge of continental France with 142,346 inhabitants (2023), Brest forms Western Brittany's largest metropolitan area, ranking third behind Nantes and Rennes in Brittany, and the 25th most populous city in France (2019); moreover, Brest provides services to the one million inhabitants of Western Brittany. Although Brest is by far the largest city in Finistère, the préfecture of the department is in the much smaller town of Quimper.