London
There are many accents traditionally associated with London. The most well known of the London accents long ago acquired the Cockney label from London's East End, which is heard both in London itself, and across the wider South East England region more generally. The accent of a 21st-century Londoner varies widely; what is becoming more and more common amongst the under-30s however is some fusion of Cockney with a whole array of ethnic accents, in particular Caribbean, which form an accent labelled Multicultural London English (MLE). The other widely heard and spoken accent is RP (Received Pronunciation) in various forms, which can often be heard in the media and many of other traditional professions and beyond, although this accent is not limited to London and South East England, and can also be heard selectively throughout the whole UK amongst certain social groupings. Since the turn of the century the Cockney dialect is less common in the East End and has 'migrated' east to Havering and the county of Essex.
General American
Though General American accents are not commonly perceived as associated with any region, their sound system does have traceable regional origins: specifically, the English of the non-coastal Northeastern United States in the very early twentieth century. This includes western New England and the area to its immediate west, settled by members of the same dialect community: interior Pennsylvania, upstate New York, and the adjacent "Midwest" or Great Lakes region. However, since the early to middle twentieth century, deviance away from General American sounds started occurring, and may be ongoing, in the eastern Great Lakes region due to its Northern Cities Vowel Shift (NCVS) towards a unique Inland Northern accent (often now associated with the region's urban centers, like Chicago and Detroit) and in the western Great Lakes region towards a unique North Central accent (often associated with Minnesota, Wisconsin, and North Dakota).