Tiananmen Square: Beijing, China
One of the largest public squares in the world is also home to one of the world's largest cover-ups. In the spring of 1989, Tiananmen Square became the site of the largest anti-government protest in the 20th century. When political leader Hu Yaobang died, it triggered millions of students to fill the square to demand the kind of democracy Hu symbolized. After seven weeks of protests, the People's Liberation Army took control of Tiananmen Square, killing hundreds and injuring thousands. Since then, the Chinese government has continued to try to cover-up the events, and even on the 20th anniversary in 2009, it blocked Internet access to any information about the event and wouldn't allow foreign journalists access to Tiananmen Square.