The seriousness of the threat to the global financial system is clearly evident in this story from Forbes:
It appears that a big European bank got close to failure last night. European banks, especially French banks, rely heavily on funding in the wholesale money markets. It appears that a major bank was having difficulty funding its immediate liquidity needs. The cavalry was called in and has come to the successful rescue.
The announcement made by central bankers this morning is a form of quantitative easing (QE). The central banks create money out of thin air and swap it for collateral. Freshly printed dollars are being injected into the economy.