It's tricky to verify the existence of super heavy elements; you have to fuse very short-lived materials, hope you get some useful atoms, and wait for someone else to reproduce your achievement. However, scientists at a particle accelerator lab in Germany have managed that rare feat by creating and confirming Element 117, the heaviest substance observed so far. It was produced by smashing together thousands of calcium 48 and berkelium 249 atoms, and is about 40 percent heavier than lead.
Not that you'll get to see the fruits of that labor in person. The team created just four atoms, and those examples decayed into other elements within milliseconds. Even so, that should be enough to get Element 117 both a proper spot on the periodic table and a better name than the rather awkward "Ununseptium." The decay also produced isotopes of additional elements whose half-life could be measured in hours, which is exceptionally long -- that suggests that there are undiscovered super heavy materials that could be relatively stable.