A data centre is a facility used to house computer systems and associated components, such as telecommunications and storage systems.

The SuperNAP, with NAP standing for Network Access Point, houses the virtualised infrastructures of all the major cloud providers in the United States - including that of VMware - as well as the "clouds" of many US federal agencies and private businesses in the healthcare and banking sectors, according to Jason Mendenhall, the executive vice president of cloud at Switch Communications, which owns and operates the data centre.

"There are other organisations…I can neither confirm nor deny their presence here. But we are involved in top-security projects," Mendenhall said.

Las Vegas was selected because it is considered "the safest city in America" from a natural-disaster standpoint.

He said the well-guarded facility - which covers 36,000 square metres and is the size of 11 American football fields - draws 100 megawatts of electricity, which is enough for two large luxury hotels. The data centre also employs a custom cooling system that can automatically switch between four different cooling options to deliver the most efficient cooling for current conditions.

Visitors to the facility are welcomed by big pistol-toting guards with military or law-enforcement backgrounds who collect ID cards or passports. The guards seem to be omnipresent, monitoring each visitors' every move as they pass through card-controlled security zones.

Taking photographs and videos inside the compound is prohibited. "We have some sensitive customers here. They don't want photos to be taken," Mendenhall said.

When asked by a visitor how many guards were employed at the data centre, he replied: "As many as we need."