The Mariana Trench The deepest place on Earth: a subduction trench reaching 10,935 meters at Challenger Deep, with its own fauna, chemistry, and a handful of human visitors.
Fossilization The rare sequence of processes that preserves remains or traces of ancient organisms in the rock record.
The Rock Cycle The model describing how igneous, sedimentary, and metamorphic rocks form and transform over geological time.
Plate Tectonics The theory that Earth's outer shell consists of moving plates whose interactions build mountains, open oceans, and trigger earthquakes and volcanoes.