Imagine going to a doctor who never uses a stethoscope or takes your temperature. Instead, this doctor just asks you to talk about your thoughts and dreams. That is close to what Sigmund Freud did. Freud was born on May 6, 1856, in what is now the Czech Republic. He grew up in Vienna, Austria, and became a doctor who studied the unconscious mind -- the part of your brain that works without you knowing it. Freud believed that hidden thoughts and memories could cause problems like worry and sadness. He created a method called talk therapy, where patients lay on a couch and described whatever came to mind. Freud also studied dreams. He thought dreams were a window into the subconscious, revealing wishes and fears that people kept buried. He published a famous book called The Interpretation of Dreams in 1899. Not all of Freud's ideas held up over time, and scientists later found that many of his theories could not be tested or proved. But his biggest contribution was the idea that talking about your feelings is a valid form of treatment. Today, millions of people visit therapists who use methods built on the foundation Freud created.