Behind the headlines, these firms help form the foundation of the IT industry -- and the modern world wouldn't work without them
Crown Castle International
Wireless connectivity might seem like a ubiquitous and intangible product, but it doesn't happen without thousands of tall metal structures festooned with electronics and radio transmitter. The famous companies whose names are plastered all over your credit card bill in many cases can't be bothered with this kind of nuts and bolts stuff, so they turn to infrastructure companies like Crown Castle International. Crown Castle is based in the United States and supplies the wireless backbone in 68 of the 100 largest U.S. cities; elsewhere it's even more omnipresent, reaching 92 percent of Australian customers. Your cellphone carrier would like you to blame them when you drop a call.
Pictured: This rural eyesore provides delicious mobile connectivity to rural Britain, courtesy of Crown Castle.