1) 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.

2) The Northern Lights, also known as the Aurora Borealis, are natural light displays that occur in the polar regions due to interactions between the Earth's magnetic field and solar particles.

3) Mount Kilimanjaro in Tanzania is the highest mountain in Africa and attracts climbers from around the world.

4) The word "flower" contains two vowels: O and E.