Based on the location described in the original novel, the Glimmer is said to be somewhere in the southern United States, specifically in a coastal region. You probably wouldn’t guess it by watching the film, but “Annihilation” was actually filmed in England, in parkland near the famous Pinewood Studios. In a New York Times “Anatomy of Scene” video, Alex Garland explained how the Shimmer’s design came about.
One of the most important elements to start with is the Fisherman’s Hut, which the team encounters after entering the Shimmer for the first time. Set designer Michelle Day created the shack’s derelict, sunken design, which was in direct contrast to the original idea of a more quaint-looking dwelling. The cabin looked even more impressive considering the beautiful, lush, green setting in which it is set.
Referring to the Shimmer’s natural landscape, Garland said, “Most of what you see there is constructed in some way.” He explained that much of the visible foliage was placed there by set decorators, so the Shimmer doesn’t like it England, but more like a mutated, twisted shoreline in the American South.