Submission + - The World's Longest-Running Lab Experiment Is Almost 100 Years Old (sciencealert.com) 1
Three years later, in 1930, Parnell cut the funnel's stem, like a ribbon at an event, heralding the start of the Pitch Drop Experiment. From then on, the black substance began to flow.
At least, that is, in a manner of speaking. At room temperature pitch might look solid, but it is actually a fluid 100 billion times more viscous than water.