The National Science Foundation's Ocean Observatories Initiative Regional Cabled Array is transforming how scientists, educators and the public observe and interact with the ocean. This underwater cabled observatory brings the Internet into the ocean through use of high power and bandwidth fiber optic cables that provide abundant power and two-way, interactive communications to novel sensor arrays on the seafloor and throughout the water column. The observatory includes  six state-of-the-art  instrumented, full water column moorings (up to 2900 m, >9500 ft water depth) hosting instrumented  wire crawlers, winched science pods, and platforms to study  linkages  among  physical,  biological  and chemical processes   spanning   blue   water   to  coastal   systems   along   the Cascadia  Margin.  The  coastal  array  is  located  at  highly productive   coastal   sites  strongly   impacted   by  the  California Current, upwelling, ocean acidification, and hypoxia events. The network also includes cutting edge seafloor sensors focused on understanding active volcanism, life in extreme environments, seismicity, and biogeochemical processes and fluxes in actively forming  gas hydrate  systems.  Two-way  24/7/365  communication with direct connection  to the Internet,  with expansion  up to 240 Gb/s  and  high  power  (8  kW),  allow  highly  interactive, rapid responses  with adaptive  sampling  to events such as formation  of thin layers, large storms, internal waves, volcanic eruptions, and earthquakes.