Step Inside Apple’s Data Center in Arizona, Courtesy of The Arizona Republic

It’s rare that the public gets a look inside the engines powering the world’s biggest companies.

Apple, which earlier this month became the first trillion-dollar public company in the world, recently opened the doors of its massive Mesa, Arizona, data center to a reporter and a photographer working for The Arizona Republic.

Data centers are tech companies’ most business-critical assets, storing data for and powering the digital services we all use daily. They’re also incredibly expensive to build and operate, and tech giants hold much of the innovation they do internally to improve their performance and lower their cost close to the vest, considering it a key competitive advantage.

Sometimes, however – doing it purely to meet some publicity needs – they give the press a peek inside. In Mesa, Apple’s publicity needs appear to be around highlighting the campus’s economic-development value to the state.

As they do in exchange for building offices and factories, companies usually get tax breaks for building data centers from the cities, counties, and states they choose to build them in. While data centers hire relatively few workers, they enable local politicians who lobby for them to paint their cities or states as tech-friendly and themselves as fighting to create high-paying tech jobs.

Related:Apple Data Center and Servers FAQ

Arizona Governor Doug Ducey, whose current reelection campaign trail was expected to include a stop at the Apple data center Wednesday, has been claiming the company’s decision to build the facility in the state in 2015 as a big jobs victory during his first year in office, according to The Republic.

The company has hired about 150 people at the 1.3 million-square foot campus since it opened two years ago. Apple completed the latest capacity expansion at the site in April, adding several data halls, and Ducey was expected to pay a visit to highlight the expansion.

See The Republic’s story for a look inside the data center.