This project is an environmental and technological history of the nuclear age in Ukraine. It highlights major peaceful and military activities from the dawn of the nuclear age, 1930-present. Ukrainian history encompasses all processes and experiences of the nuclear world: uranium mining, the arms race and non-proliferation, nuclear missiles and atomic bomb research, the unrestrained push for nuclear power, accidents and radioactive pollution. This project argues that Eastern Europe in general and Ukraine in particular are crucial to fully understand the global nuclear order. It draws on unique primary sources to extend this history in new ways: by adopting postcolonial and envirotechnical perspectives and by analyzing simultaneously civilian and military applications. The project considers both the impact on nature and nature’s agency, adaptation, and resistance to nuclear infrastructure, and the emergence of new and unpredictable geographies, landscapes, and power relationships that accompanied nuclear development. Beyond the dichotomy between colonizer and colonized, the project will unravel the complex material, environmental and institutional entanglements, from uranium ore to fuel, from production to pollution, and from research to widespread applications that the development of atomic energy and weapons entails. The Russian invasion of Ukraine confirms dramatically the relevance of the region to understand inner workings and inherent risks of the global nuclear order.