1) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.

2) The Amazon Rainforest, located in South America, is the largest tropical rainforest in the world, covering an area of approximately 5.5 million square kilometers (2.1 million square miles). It is known for its exceptional biodiversity and plays a crucial role in the global ecosystem.

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

4) The Alps, located in Europe, are a popular destination for skiing, mountaineering, and hiking.