Designed by Japanese architect Sou Fujimoto, the room takes inspiration from the minimalist forms featured in the retailer's spring/summer collection.
Those who enter the space can interact with long, cone-like towers of light that shift in response to their movements.
Thanks to mirrors across its walls, these 'trees' are multiplied to create the effect of a forest, albeit one made entirely of light. Sounds and smoke add to the effect.
Visitors are encouraged to share their experience of Forest of Light via Instagram using the hashtag #COSxSouFujimoto.
Cos has created an installation and concept store at Milan Design Week, also known as Salone del Mobile, every year since 2011. The event is considered to be the world’s largest design fair.
Martin Andersson, head of menswear design at Cos, said: "Sou Fujimoto has really grasped the COS aesthetic, creating an installation that is so special in its simplicity and surprising in its approach."
Karin Gustafsson, head of womenswear design, added: "It has been great working with Sou Fujimoto on this project, we have never had such a beautifully simple installation focusing on light and the effect is incredible".
Nike, PepsiCo and Marni have allso unveiled concept stores at this year's design festival.