Stock markets everywhere are a disaster on Tuesday. But a few asset classes are rallying, and one staging a furious rally is US Treasury bonds. On Tuesday morning, the 10-year bond yield had fallen back below 2.2%, while the 30-year bond was down at 2.86%, the lowest level for the 30-year since 2012. Remember: falling yields mean bond prices are rising. Back in November, DoubleLine's Jeff Gundlach said that 2.2% was the "line in the sand" on the 10-year yield, and said that discounting the wild morning of October 15, that level has pretty much held for the 10-year. And so with volatility back in the market on Tuesday and the 10-year once again flirting with 2.2% we will see if that level holds again. Stocks in the US are taking their lead from markets in Asia, which dropped hard overnight as the Shanghai Composite fell more than 5%. Stocks in Europe were also selling off in a big way as concerns over the political situation in Greece have flared up after the presidential election was pulled forward by two months on Monday. Business Insider's Mike Bird has the full breakdown of the Greece situation here. And while Treaury bonds were rallying as investors sought safety amid equity instability, gold was also surging. SEE ALSO: Markets Everywhere Are Tanking Join the conversation about this story »