In 2000, Ecuador scrapped its own currency and adopted the US dollar overnight

After the sucre lost most of its value in a single year during a banking crisis, President Jamil Mahuad abolished it in January 2000 and made the US dollar Ecuador's sole legal currency. The move cost Ecuador control over its own monetary policy for good, but it ended the hyperinflation spiral, a quarter-century later, dollarization remains intact and popular.

— Wikipedia contributors, 1998-99 Ecuador financial crisis — Dollarization decreed January 9, 2000