A sudden happening that brings good fortune (as a sudden opportunity to make money).

synonyms: bonanza, boom, bunce, godsend, gravy, manna from heaven, windfall.

Dutch: godsgeschenk, saus, buitenkans, buitenkansje, explosie, kaan
Polish: manna z nieba

A large migration of people to a newly discovered gold field.

Dutch: goudkoorts