1. The US government covered up the deaths of 300 people
In Tulsa, contact between a black man and a white woman led to the white people being enraged. This was in 1921. The whites wanted to lynch the black man, and mobs of black and white men gathered near the jail. A gunshot went off, which resulted in the most violent domestic incident in US history. Tulsa was firebombed by white pilots, and the Black Wall Street, which was a place where well to do black people lived, was razed to the ground. After the riot ended, 300 black people had died. Incredibly, the cover up was so complete, for nearly 80 years, the official death toll stood at 39. Only in the 90s did we discover what actually happened, which is why this tops the list of the biggest government cover ups of all time.