Fascinatingly, geologists believe this blob was formed by the remnants of the seafloor of an ancient ocean called the Tethys Ocean that sat between two supercontinents called Laurasia and Gondwana ...

This story appears in the August 2010 issue of National Geographic magazine. Thirty-seven million years ago, in the waters of the prehistoric Tethys Ocean, a sinuous, 50-foot-long beast with ...