The US $40 trillion debt has dominated global headlines, but the next debt crisis may originate from the eurozone, not the US. The US faces significant fiscal challenges, with an estimated $95 trillion gap in Social Security and Medicare over 75 years, alongside federal debt projected at 101% of GDP by 2026. However, the eurozone's hidden fiscal burden is at least as large, with net accrued public-pension liabilities around 150% of GDP. Several factors suggest the eurozone is more vulnerable: the US dollar remains the world reserve currency, whereas eurozone governments exhibit fiscal denial, refusing spending cuts.Euro-area sovereign assets have yielded negative real returns since 2021, dampening global investor appetite. The reported Maastricht debt for the eurozone significantly understates the full balance-sheet liabilities and implicit commitments of public administrations. The global bond sell-off indicates markets perceive that central banks will no longer mask governments' fiscal irresponsibility. Developed economies have pushed debt-funded policies beyond their fiscal, economic, and inflationary limits, leading to persistent deficits, weakened economies, and inflation.While US Treasury yields serve as a global benchmark, the eurozone is more precarious because member states borrow in a currency they don't control, and governments resist reducing spending. The repricing of long-term sovereign bonds is global, driven by inflation risk, fiscal deterioration, high debt supply, and central banks' inability to conceal fiscal irresponsibility. German and French bond yields are rising, reflecting the weakening core of the eurozone.The eurozone lacks institutional flexibility, discipline, and an open market approach, making it susceptible to a systemic crisis. Proposed "savings and banking union" and central bank digital currency projects raise concerns about interventionism rather than market appeal. The core issue is not just the absolute debt level, but the combination of high borrowing, large government, high taxes, and a lack of real growth capacity.The solution requires credible spending cuts, lower structural deficits, stronger incentives for private investment, and regulatory reforms that boost productivity and economic growth. Without these changes, despite US debt challenges, the eurozone's inherent problems make it a more probable epicenter for the next sovereign crisis.