United Nations peace operations can have both positive and negative, intended as well as unintended, impacts on their deployment area. Their physical presence on the ground may benefit the host country by improving access to safe water and sanitation but may also (inadvertently) contribute to environmental degradation and damages on cultural heritage sites. This chapter makes an original contribution to the peacekeeping literature by drawing attention to the (often neglected) issue of the material impact of UN peace missions. Jointly exploring the protection of the environment and of cultural heritage, it first assesses the scope of UN peace missions' material impact. Deepening the comparison between the ecological and cultural footprint of UN peace operations, it then unpacks broader institutional processes and exposes transversal power dynamics within the UN system.