A tower is a tall, narrow structure that often stands alone and is designed for various purposes. Towers can be found in many forms, such as communication towers, which transmit signals for phones and television, or watchtowers, which are used for surveillance and security. They can also serve as landmarks, like the Eiffel Tower in Paris, which attracts millions of visitors each year. Towers are built using materials like steel, concrete, or stone, depending on their intended use. They can vary greatly in height, from small observation towers to skyscrapers that reach hundreds of meters into the sky. Some towers are designed for aesthetic appeal, while others focus on functionality.