Have you ever noticed that your voice sounds different in a bathroom than in your bedroom? The shape and size of a room change how sound travels. On April 11, 1888, a concert hall opened in Amsterdam, the Netherlands. It is called the Concertgebouw. That name means "concert building" in Dutch. It quickly became famous for one reason: music sounds incredible inside it. The architect, Adolf Leonard van Gendt, designed the main hall in a rectangular shape. He made the ceiling very high, about 56 feet from the floor. The walls are not perfectly smooth. They have textures and angles that bounce sound in many directions. When a musician plays a note, the sound waves hit these surfaces. They reflect and mix together. This creates a warm, rich sound that wraps around the audience. Experts say the hall has some of the best acoustics in the world. Acoustics is the science of how sound behaves in a space. The Concertgebouw's reputation grew quickly. Famous composers and musicians wanted to perform there. A world-class orchestra was created just for the building. The Royal Concertgebouw Orchestra has been performing there for over a hundred years. It is considered one of the finest orchestras on Earth.