There’s not much architectural excitement about a data center. But the windowless, big-box buildings form the climate-controlled central nervous system of online commerce and communications. They are as essential to the basic economic infrastructure of the 21st century as iron ore mines and auto assembly plants were to the 20th.

What distinguishes them is their size. Prineville’s Facebook and Apple centers are among 386 “hyperscale” data centers around the world, built and operated by the 24 biggest internet and technology companies, including Alibaba, Alphabet, Amazon, eBay, Microsoft and Yahoo. A study this year by Cisco, the Silicon Valley networking company, projected the number of hyperscale data centers to grow to 628 by 2021. Those centers could command more than half of all data center internet traffic. The United States accounts for more than half of all data center construction, Cisco said, followed by Asia, Western Europe and Latin America.

A study in 2017 by CBRE Research found that certain metropolitan regions — Chicago, Detroit, New Jersey, New York, Northern Virginia and Silicon Valley — were the most active areas for data center construction in the United States.

Like the big industrial projects of the previous century, the investments that Facebook, Apple and their competitors have made in land, buildings and equipment are considerable, typically more than $1 billion each. The centers consume prodigious amounts of electricity and water, just like factories. Property tax breaks that Oregon and other states use to lure data centers also are comparable. What is different is slim staffing.