Low Tiberium contamination
The Pentagon is the Command Center of the United States Department of Defense and is now a vital element of the GDI defence system for the United States Eastern Seaboard, located at 48 N. Rotary Road, Arlington, Virginia 22211. Its mailing address is "Washington, DC 20301." As a symbol of the US military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.
Built by Philadelphia contractor John McShain, the building was dedicated on January 15, 1943. It is the highest-capacity office building in the world and one of the world's largest buildings in terms of floor area. It houses approximately 23,000 military and civilian employees and about 3,000 non-defense support personnel. It has five sides, five floors above ground (plus two basement levels), and five ring corridors per floor with a total of 17.5 miles (28 km) of corridors.
During the First Tiberium War, Seth ordered an ambitious commander to attack the Pentagon, supposedly in hopes to render the United States' center of military operations useless. However, this plan was never carried out. Considering the strength of the United States during the First Tiberium War, it was likely the mission was meant to be a failure as a way to get rid of the commander.
In March 2047, the Pentagon came under heavy attack from Nod forces shortly after the Philadelphia's destruction and Nixon's capture, rendering the Pentagon the sole remaining major GDI command center. Nod Militia managed to destroy the power supply to its Watchtower defences, rendering it almost completely defenceless. Thanks to the timely intervention of a resourceful GDI commander the building was successfully defended, with help from APC platoons and Grenadier squads that also arrived in the nick of time. This also proved the point where attacking the Pentagon was a suicide mission.
During the First Tiberium War, Seth was about to send a rising Nod commander to attack the Pentagon knowing full well it was a suicide mission. Kane however revoked the order. Ironically, at the start of the Third Tiberium War, this would eventually be proven true as a less competent Nod officer attempted to take out GDI's last global command center, only to be killed doing so by the GDI commander.