A harbor is a body of water where ships, boats and barges seek shelter from stormy weather, or are stored for future use. The term "harbor", referring primarily to a sheltered body of water, is often used interchangeably with "port", which is a man-made facility built for loading and unloading vessels and dropping off and picking up passengers. Ports usually include one or more harbors. Alexandria Port is an example of a port with two harbors.Harbors can be natural or artificial. An artificial harbor can have deliberately constructed breakwaters, sea walls, or they can be constructed by dredging, which requires maintenance by further periodic dredging.