1) The musical "The Phantom of the Opera" has been running in London's West End since 1986, making it the longest-running musical in history.

2) The novel "To Kill a Mockingbird" by Harper Lee has been translated into more than 40 languages and has sold over 40 million copies worldwide.

3) The Dead Sea, located between Jordan and Israel, is the lowest point on Earth's surface. Its saltwater is so dense that people can easily float on its surface.

4) The hamburger, consisting of a ground beef patty served between two buns, is an iconic American food. It has gained global popularity and countless variations, from classic cheeseburgers to gourmet creations with unique toppings and sauces. The invention of the hamburger is often attributed to Louis Lassen, a Danish immigrant in Connecticut, who served the first hamburger in the early 20th century. Today, hamburgers are a staple in fast-food chains, casual diners, and backyard barbecues around the world.