Cabin lighting and the Sun compete to illuminate this picture of Concordia research station in Antarctica.
Based near the South Pole the Concordia crew live without sunlight for four months during the winter period. During this time no supplies or outside help can arrive at the base due to the extreme cold.
The crew have to be self-sufficient and rely on generators that provide electricity and artificial lighting.
ESA is studying the effects of isolation preparing for future spaceflight missions.
Credits: ESA/IPEV/PNRA - A. Kumar