Belfast (meaning: "mouth of the sandbanks") is the capital and largest city of Northern Ireland, the second-largest city in Ireland after Dublin, and is situated around the River Lagan, which runs through the city. It is a port city known as the birthplace of the RMS Titanic, and for its political murals, documenting the ‘Troubles’ of the 20th century. Today, Belfast remains a centre for industry, as well as the arts, higher education, business, and law, and is the economic engine of Northern Ireland. The city suffered greatly during the period of conflict called "the Troubles", but latterly has undergone a sustained period of calm, free from the intense political violence of former years, and substantial economic and commercial growth. Additionally, Belfast city centre has undergone considerable expansion and regeneration in recent years, notably around Victoria Square.

Reykjavík is the capital and largest city of Iceland. It has a latitude of 64°08' N, making it the world's northernmost capital of a sovereign state, and is a popular tourist destination. It is the heart of Icelands's cultural, economic and governmental activity. The city itself is spread out, with sprawling suburbs. The city centre, however, is a very small area characterized by eclectic and colourful houses, with good shopping, dining, and drinking.

Dublin is the largest and capital city of Ireland. The English name is derived from the Irish name Dubh Linn, meaning "black pool". It is a primate city with an urban population of over 1 million, containing almost 25% of the country's population. Dublin is situated near the midpoint of Ireland's east coast, at the mouth of the River Liffey, and at the centre of the Dublin Region. The city is listed by the Globalization and World Cities Research Network (GaWC) as a global city, with a ranking of "Alpha-", placing it among the top thirty cities in the world. It is a historical and contemporary centre for education, the arts, administration, economy and industry.