An alien Nazi structure that changed history, a strange Soviet monolith known as the Tower of Death, and a concrete ocean giant are deserted engineering projects, and new discoveries reveal how they were built and why they were abandoned.
By entering your email address, you agree to our Terms of Use and acknowledge the Privacy Policy. discovery and its affiliates may use your email address to provide updates, ads, and offers.
To withdraw your consent or learn more about your rights, see the Privacy Policy.