A Wide Area Network is the largest private network available. It's made up of multiple LANs (Land Area Networks) and/or MANs (Metropolitan Area Networks). Since private networks stay off the public internet, businesses can securely connect headquarters with branch offices and other facilities. WANs allow businesses to privately send data and voice transmissions without concern of someone hacking via the Intenet. A data center or a dedicated colocation server facility can also be connected to a WAN, and can therefore connect the entire private network to the Internet with only a few firewalls. The Internet is the largest WAN, but since it is open to the public, it is not private.