The oceanic trenches are the deepest parts of the ocean floor, typically formed when one tectonic plate slides under another. Major world trenches include:
- Aleutian Trench
- Cayman Trench
- Japan Trench
- Kermadec Trench
- Kuril Trench
- Mariana Trench
- Middle America Trench
- Peru-Chile Trench
- Puerto Rico Trench
- Tonga Trench