Trilobites went extinct around 250 million years ago.
The Louvre opened as a public museum in 1793 in Paris, France.
LED stands for light-emitting diode.
Hello in Arabic is salam.
The uranium and plutonium bombs dropped by the U.S. killed around 200,000 Japanese people in 1945.
Alfred Hitchcock was born in 1899 and died in 1980.
The tallest building in Chicago is the Willis Tower at 1,451 feet tall.