The U.S. bond market sets the risk-free rate against which every other asset is measured, which is why Ray Dalio calls it "the backbone of all markets." But this week it's also become the biggest story in global finance.

Long-term Treasury yields have spiked to their highest levels in decades, with the 10-year over 4.6% and the 30-year topping 5.1%. The bond sell-off has sent mortgage rates climbing again, spooked stock markets, and inspired a familiar safe-haven pattern with gold up, the dollar down, and Bitcoin surging to $111,000.