1) The first photograph of a black hole was captured in 2019 using a network of telescopes around the world.

2) The word "mountain" contains three vowels: O, U, and A.

3) The world's largest species of shark, the whale shark, can reach lengths of up to 40 feet (12 meters) and weigh over 20 tons.

4) Robert Downey Jr. is an American actor known for his portrayal of Iron Man in the Marvel Cinematic Universe. He has also starred in films such as "Sherlock Holmes," "Chaplin," and "Tropic Thunder," and has received critical acclaim and commercial success for his performances.