Runit is a small island located in the Marshall Islands, known for its unique history and environmental significance. It was the site of a nuclear testing program conducted by the United States during the 1940s and 1950s, which left behind radioactive waste. The most notable feature on the island is the Cactus Dome, a concrete structure built to contain the radioactive materials. Today, Runit serves as a reminder of the impacts of nuclear testing on the environment and local communities. The island is largely uninhabited, but it remains a point of interest for researchers studying the long-term effects of radiation and the challenges of managing nuclear waste.