The global financial crisis was caused by a large increase in savings from 2000-2007 that sought higher yields than US Treasury bonds, generating asset bubbles around the world. When the bubbles burst, governments and banks faced questions about their solvency as asset prices fell but debt levels remained. This interconnected the global financial system and risk of default by one country threatened others through trade links and credit default swaps. The eurozone crisis emerged from these conditions and was exacerbated by fiscal issues in Greece and other countries that masked their debt levels. Rising government debt and loss of confidence in sovereign debt further drove the crisis.