Today, alongside partners in Asia, the two Internet giants announced they will build the longest and highest capacity undersea fiber-optic cable between the two continents. Once completed, the Pacific Light Cable Network—PLCN for short—will stretch 8,000 miles from Los Angeles to Hong Kong with an estimated capacity of 120 terabits-per-second. That's about twice the capacity of the Oregon-to-Japan cable "Faster," which Google recently launched with several telco partners. Construction of the new cable will begin this year, and it should come online in 2018.

The move highlights the larger role that tech giants like Facebook, Google, and Microsoft are playing in the construction of telecommunications infrastructure. Just last May, Facebook and Microsoft teamed up to build a new 4,100 mile cable connecting Virginia to Spain. PLCN is the sixth undersea cable that Google has invested in.