A manhole cover is a removable lid that sits on top of a manhole, which is an opening in the ground that provides access to underground utilities like sewer systems, water lines, and electric cables. These covers are typically made of heavy materials such as cast iron or steel to withstand the weight of vehicles and prevent accidents. Manhole covers are designed to fit securely in place, preventing unauthorized access and keeping debris out of the underground systems. They often have a circular shape, which helps them resist being dislodged by traffic. Some covers feature designs or markings that indicate the utility company responsible for the infrastructure below.