Greenland, Iceland, and the United Kingdom Chokepoint

The GIUK gap is an area in the northern Atlantic Ocean that forms a naval warfare chokepoint.  Its name (typically used in military topics) is an acronym for *G*reenland, *I*celand, and the *U*nited *K*ingdom, the gap being the open ocean between these landmasses.
photo source: file from wikimedia/GIUK_gap