Mili's airstrip and surrounding wartime remains are the atoll's most substantial sight. Japan built Mili into a defended air base, and traces of that military landscape still sit close to the modern village and runway.
The remains are not curated. Expect scattered concrete, rusting fragments, overgrowth, and the need for someone local who knows what you are looking at. That lack of polish makes the place more affecting, but it also means you should not wander through private or village land uninvited.