In 2016 a drilling expedition off Mexico's Yucatán Peninsula brought up core from 670 meters beneath the seafloor, inside the Chicxulub impact structure. The samples contain shattered granite bedrock hit by the asteroid 66 million years ago, which blasted open the 180-kilometer crater and led to the extinction of most life on Earth, including the non-avian dinosaurs.
via Scientists hit pay dirt in drilling of dinosaur-killing impact crater | Science