$1 billion is a large sum of money that equals 1,000 million dollars. It is often used to measure the value of companies, investments, or government budgets. For example, a successful startup might be valued at $1 billion, making it a "unicorn" in the business world. In everyday terms, if you had $1 billion and spent $1 every second, it would take you over 31 years to spend it all. This amount can fund significant projects, such as building hospitals or schools, and is often discussed in the context of philanthropy and economic development.