Documented cases, by city.

Amsterdam

Netherlands

Amsterdam is the capital and largest city of the Netherlands. It has a population of 933,680 in June 2024 within the city proper, 1,457,018 in the urban area and 2,480,394 in the metropolitan area. Located in the Dutch province of North Holland, Amsterdam is colloquially referred to as the "Venice of the North", for its large number of canals, now a UNESCO World Heritage Site.

Alphen aan den Rijn

Netherlands

Alphen aan den Rijn is a city and municipality in the western Netherlands, in the province of South Holland. The city is situated on the banks of the river Oude Rijn, where the river Gouwe branches off. The municipality had a population of 112,587 in 2021, and covers an area of 132.50 km2 (51.16 sq mi) of which 6.27 km2 (2.42 sq mi) is water.

London

United Kingdom

London is the capital and largest city of England and the United Kingdom, with a population of 9.1 million people in 2024. Its wider metropolitan area is the largest in Western Europe, with a population of 15.1 million. London stands on the River Thames in southeast England, at the head of a 50-mile (80 km) tidal estuary down to the North Sea, and has been a major settlement for nearly 2,000 years. Its ancient core and financial centre, the City of London, was founded by the Romans as Londinium and has retained its medieval boundaries. The City of Westminster, to the west of the City of London, has been the site of the national government and parliament for centuries. London grew rapidly in the 19th century, becoming the world's largest city at the time. Since the 19th century the name "London" has referred to the metropolis around the City of London, historically split among the counties of Middlesex, Essex, Surrey, Kent and Hertfordshire. Since 1965 it has largely comprised the administrative area of Greater London, governed by 33 local authorities and the Greater London Authority.

Rome

Italy

Rome is the capital city and most populated comune (municipality) of Italy. It is also the administrative centre of the Lazio region and of the Metropolitan City of Rome. A special comune named Roma Capitale with a population of 2.7 million in an area of 1,287.36 km2 (497.1 mi2), Rome is the third most populous city in the European Union by population within city limits. The Metropolitan City of Rome Capital, with a population of 4.2 million, is the most populous metropolitan city in Italy. Its metropolitan area is the third-most populous within Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of the Tiber Valley. Vatican City is an independent country inside the city boundaries of Rome, the only existing example of a country within a city. Rome is often referred to as the "City of Seven Hills" due to its geography, and also as the "Eternal City". Rome is generally considered to be one of the cradles of Western civilization and Western Christian culture, and the centre of the Catholic Church.

Boston

United States

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 sq mi (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 4.9 million in 2023, making it the largest metropolitan area in New England and the eleventh-largest in the United States.

New York

United States

Paris

France

Paris is the capital and largest city of France, with an estimated city population of 2.04 million in an area of 105.4 km2 (40.7 sq mi), and a metropolitan population of 13.2 million as of January 2026. Located on the river Seine in the centre of the Île-de-France region, it is the largest metropolitan area and fourth-most populous city in the European Union (EU). Nicknamed the "City of Light", partly because of its role in the Age of Enlightenment, Paris has been one of the world's major centres of finance, diplomacy, commerce, culture, fashion, and gastronomy since the 17th century.