There Are Five Oceans, Not Seven

The "Seven Seas" is an ancient phrase — but modern geography recognizes five oceans:

1. Pacific Ocean — largest (165M km²), deepest (Mariana Trench 10,935 m).
2. Atlantic Ocean — second largest (106M km²), saltiest.
3. Indian Ocean — third (70M km²), warmest.
4. Southern (Antarctic) Ocean — recognized 2000 (IHO); encircles Antarctica; ACC current.
5. Arctic Ocean — smallest (14M km²), shallowest, sea-ice covered.

Why Not Seven?

Historically, "Seven Seas" referred to trade routes (Mediterranean, Red Sea, Persian Gulf, etc.) or subdivided the Pacific/Atlantic (North/South). The International Hydrographic Organization (IHO) standardized the five-ocean model in 2000 (3rd edition, Limits of Oceans and Seas).

All are interconnected — one world ocean.