The weak U.S. currency is changing the lives of billions. Some are getting richer, some are barely making it. From a fish market in Tokyo to a sushi restaurant in Los Angeles, a look at why the greenback matters.

Some say it's epochal, others merely cyclical. But part of it boils down to supply and demand: The world is awash in dollars these days.

Times staff writer Jeffrey Fleishman in Cairo wrote this article with files from staff writers Bruce Wallace in Tokyo; Don Lee in Yiwu, China; Henry Chu in Noida, India; Sergei L. Loiko in Kogalym, Russia; Noha El-Hennawy in Cairo; a Times staff writer in Harare, Zimbabwe; Achrene Sicakyuz in Cherbourg, France; Geraldine Baum in Paris; Louise Roug in New York; Carol J. Williams in Havana; Deedee Correll in Bennett, Colo.; and Teresa Watanabe in Los Angeles.