Late last year, scientists with the OPERA collaboration in Gran Sasso, Italy reported an incredible finding: neutrinos that appeared to be moving faster than the speed of light. In February, the OPERA researchers found a couple small problems with their experimental set-up, calling into question the original faster-than-light neutrino result. The event highlighted the difficulty of science at the edge of the unknown — and neutrinos are especially tricky.

More often than not, neutrino experiments throughout history have turned up perplexing results. While most of these experiments didn’t get the high-profile attention that disputing Einstein provides, they’ve challenged scientists and helped them learn ever more about the natural world. Wired Science takes a look at some of the strangest historical neutrino results and the findings that still have scientists scratching their heads.