A Time Ball is a large, spherical object that is dropped at a specific time to signal the exact hour. Historically, it was used in the 19th century as a way for ships in harbors to synchronize their chronometers, which were essential for navigation. The most famous time ball is located at Greenwich Observatory in London, where it drops at 1 PM every day. The mechanism of a time ball typically involves a system of pulleys and weights. When the time arrives, the ball is released, falling to the ground, which serves as a visual cue for those nearby. Time balls were crucial before the advent of modern timekeeping devices and are now mostly of historical interest.