Melting pot

Melting pots have literally been around from time immemorial, but in the sense of a metaphor for a place where a variety of races, cultures, or individuals assimilate into a cohesive whole or a process of blending that often results in invigoration or novelty, it dates from the late 19th century. It is not known who actually first used the metaphor in this context, but British author, Israel Zangwill, certainly popularised it with his play The Melting Pot written in 1904, in which he likened America to a melting pot.