Russian scientists have now spotted a total of seven craters, five of which are in the Yamal Peninsula. Two of those holes have since turned into lakes. And one giant crater is rimmed by a ring of at least 20 mini-craters, the Siberian Times reported. Dozens more Siberian craters are likely still out there, said Moscow scientist Vasily Bogoyavlensky of the Oil and Gas Research Institute, calling for an “urgent” investigation.