After banks kept collapsing, one Swiss city set the world's bank capital rules

Starting in 1988, central bankers meeting in Basel, Switzerland agreed on minimum capital requirements banks must hold against their loans, designed so a bank can absorb losses without collapsing or needing a taxpayer bailout. The rules have been revised twice since — Basel II after accounting scandals, Basel III after the 2008 crisis — each time because the previous version wasn't strict enough.

— Basel Committee on Banking Supervision, Basel Accords — First accord, 1988