Wall Street is where people buy and sell different kinds of money. People on Wall Street buy and sell stocks, bonds, and other investments. They buy stocks when they think they will go up in value, and sell them when they think they will go down in value. They also buy and sell bonds, which are like IOUs or loans, and other investments such as real estate, gold, and oil. Some people make a lot of money on Wall Street while others lose money. It's important to research investments and make decisions carefully.