Minuteman Missile National Historic Site
This place used to be the bomb. A very big bomb. Now it is just a cool historical gem located right outside the Badlands.
During the Cold War there were missile silos scattered all around the Dakotas to battle against the nuclear escalation with the USSR. I grew up hearing that these were located there but getting to see a missile in the silo (decommissioned) was quite an ominous feeling to it. Walking through the museum brings to light how scary of a time it was for many people.