Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire "New England" region. The city proper had a 2009 estimated population of 645,169, making it the twentieth largest in the country. It is also the anchor of a substantially larger metropolitan area called  "Greater Boston", home to 4.5 million people and the tenth-largest metropolitan area in the country. Greater Boston as a commuting region includes six Massachusetts counties:  "Essex", "Middlesex","Norfolk", "Suffolk", "Plymouth", "Worcester", northern "Bristol" County, all of "Rhode Island" and parts of "New Hampshire"; it is home to 7.6 million people, making it the fifth-largest Combined Statistical Area in the United States.

Rotterdam is the second-largest city in the Netherlands and the largest port in Europe. Starting as a dam on the Rotte river, Rotterdam has grown into a major international commercial centre. Its strategic location at the Rhine-Meuse-Scheldt delta on the North Sea and at the heart of a massive rail, road, air and inland waterway distribution system extending throughout Europe means that Rotterdam can rightly be called the gateway to Europe. Located in the Province of South Holland, Rotterdam is in the west of the Netherlands and at the south of the Randstad. The population of the city proper was 603,425 in March 2010. The population of the greater Rotterdam area, called "Rotterdam-Rijnmond" or just "Rijnmond", is around 1.3 million people. Rotterdam is one of Europe's most vibrant and multicultural cities.