The place where Earth's crust goes back down into the Earth is called a subduction zone.

Here's a breakdown:

* Subduction: This is the process where one tectonic plate (the denser one) slides beneath another tectonic plate.

* Zone: This refers to the area where this process occurs.

Subduction zones are often marked by:

* Volcanoes: The melted rock from the subducted plate rises to the surface, forming volcanoes.

* Earthquakes: The movement of the plates along the subduction zone causes earthquakes.

* Deep ocean trenches: The point where the subducted plate bends downward creates a deep trench in the ocean floor.