Microsoft and Facebook are building a new underwater Internet cable that will cross the Atlantic Ocean, carrying customers' data between North America and Southern Europe.



The giant tech companies say they helped design the high-speed cable to carry data for their growing numbers of online consumers and commercial customers. The project will be operated by an affiliate of Spanish telecommunications firm Telefonica, which will sell unused capacity on the cable to other customers. It will connect data hubs in Northern Virginia and Bilbao, Spain.



Internet companies often pay to use cables owned by telecommunications providers, but the new project won't be the first to be owned by a U.S. tech company. Google has invested in subsea projects across the Pacific.