In 1997, GISS showed that the earth was rapidly warming from 1866 to 1900. But by 1999, they showed the exact opposite for the same time period.
The 1997 version was destroyed on the Web Archive sometime this week, and is now empty. It was located here. I captured it on December 23.
The 1999 version has not been destroyed yet, and can still be found here :
They claim to know temperatures within 0.01 degrees, but didn’t even know the polarity of the trend.