1) Michael Phelps, an American swimmer, has won a total of 28 Olympic medals, including 23 gold medals, making him the most decorated Olympian of all time.

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) The #MeToo movement, originating in 2006 and gaining widespread attention in 2017, raised awareness about sexual harassment and assault, encouraging survivors to share their experiences and promoting discussions on consent and gender equality.

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