1) The Pacific Ocean is the largest ocean on Earth, covering more than 30% of the planet's surface.

2) The concept of sovereignty refers to the supreme authority and power of a state to govern itself, make decisions, and control its own territory without interference from external forces.

3) The Danube River, flowing through ten countries in Central and Eastern Europe, is the second-longest river in Europe. It has played a significant role in the cultural and economic development of the regions it traverses and is a popular waterway for river cruises.

4) The world's largest ocean, the Pacific Ocean, covers an area of approximately 63 million square miles.