A graphic display of USS Hartford (SSN 768) surfacing through ice during Ice Exercise 2018 (ICEX). ICEX 2018 is a five-week exercise that allows the U.S. Navy to assess its operational readiness in the Arctic, increase experience in the region, advance understanding of the Arctic environment, and continue to develop relationships with other services, allies and partner organizations. (U.S. Navy video/Released)

ARCTIC CIRCLE (March 10, 2016) USS Hartford (SSN 768) surfaces in the Arctic Circle near Ice Camp Sargo during Ice Exercise (ICEX) 2016. Servicemembers and civilians assigned to Arctic Submarine Lab clear ice from the hatches to allow for surface access. ICEX is a five-week exercise designed to research, test, and evaluate operational capabilities in the region. (U.S. Navy video by Mass Communication Specialist 2nd Class Tyler Thompson and Staff Sgt. Edward Eagerton/Released

In Ice Exercise 2018, U.S. Navy and UK Royal Navy submarines got their readiness to operate in frigid environments tested by breaking through the North Pole ice.