Manholes are openings in the ground that provide access to underground utilities, such as sewer systems, water lines, and electric cables. They are typically covered with a heavy, round lid made of metal or concrete, designed to withstand traffic and prevent accidents. Manholes are essential for maintenance and repairs, allowing workers to enter and inspect the underground infrastructure safely. The design of manholes varies, but they are usually circular to prevent the cover from falling in. They are often marked with symbols or labels indicating the type of utility they access. Regular inspections of manholes help ensure the safety and functionality of urban infrastructure.