1) 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.

2) The world's tallest waterfall is Angel Falls in Venezuela, with a height of about 3,212 feet (979 meters).

3) The sitcom "Friends" is known for its iconic Central Perk coffee shop, where the main characters often gather.

4) The United States operates under a two-party system, with the Democratic Party and the Republican Party being the two major political parties that compete in elections and shape the country's political landscape.