The Iranian Hostage Crisis began when fifty-two Americans were held hostage in Iran for 444 days, after a group of Iranian students stormed the U.S. Embassy in Tehran and took over the embassy. It was sparked as the Iranians demanded that the United States return the overthrown leader of Iran who was seeking cancer treatment to face trial for crimes he committed during his reign. This was the longest hostage crisis to ever occur in history, and this was significant as it helped to destroy the relations between Iran and the United States of America.
The Strategic Defense Initiative, nicknamed "Star Wars," was a system that was supposed to protect the United States from attack by ballistic missiles by deploying an orbital defense system that used lasers mounted on satellites orbiting the earth to shoot down missiles. This was significant as it would have been a brilliant defense system that would have rendered attacks upon the United States futile; had it been finished.
The Iran Contra affair was a scandal that occurred during the Reagan administration, where the US government secretly sold arms to Iran, who was subject to the arms embargo. It was started in order to free U.S. hostages in Iran, but the question remains whether or not President Ronald Reagan was authorized this sell of arms to the Iranians. This particular scandal is significant as it is one of the major scandals that occurred during the Reagan presidency.
The Tiananmen Square Protests were student-led demonstrations in Beijing that called for more democracy to be implemented within China. Martial law was implemented, and troops with machine guns and tanks killed at least several hundred demonstrators who attempted to block the military's advance. Perhaps most famous of this incident is the "Tank Man" image, which shows one man standing down a battalion of tanks that would likely go on to kill protestors. This particular protest within Beijing was significant as it marked the growing unpopularity of Communism.
The Gulf War, or Operation Desert Storm was waged between 35 nations (mainly the United States) against Iraq in response to Iraq's invasion of Kuwait. This particular country, Kuwait, was very important to the United States as it was a friendly country to the US and much of our oil came from this area. This increased George W. Bush's popularity and it was significant as it showed that America had the power to influence global events with the use of the military.
The "Don't ask, don't tell" became the US military policy for gays, bisexuals, and lesbians. This prohibited military personnel from discriminating against non-openly homosexuals. This was a major leap against discrimination of homosexuals and bisexuals, and this is significant as it showed the major shift in the US regarding sexual morality.
On the date of September 11, 2001, terrorists associated with Al-Qaeda hijacked four airplanes and brought down both of the towers at the world trade center, hit a wing of the Pentagon, and crashed into a field in Pennsylvania (once overpowered by the brave passengers). Around 3000 people were killed, and this was significant as it was the largest terrorist attack in history and it greatly influenced American politics with regards to Middle Eastern nations and terrorist organizations.
The Iraq War was a conflict between a US led coalition and the government of Saddam Hussein. The invasion began on March 20, 2003, in response to the assertion that Iraq had weapons of mass destruction that could pose a threat to the United States and its allies. This was was significant as it did not formally end until December 18, 2011, and marked a long and drawn out invasion by American troops to help stabilize the Iraq government after the overthrow and execution of Saddam Hussein.
North Korea tested its first nuclear weapon in 2006 which had an estimated yield of 0.2-1 kilotons. It didn't confirm that it had nuclear weapons until January 6, 2007 and in 2016 North Korea claimed to have tested a hydrogen bomb. This is significant as North Korea posses a major threat to our allies (Japan and South Korea) and the rogue regime appears to be progressing with its nuclear program.
On September 11, 2012, an Islamic militant group attacked an American diplomatic compound and killed US Ambassador J. Christopher Stevens, and attacked a CIA annex with mortars approximately one mile away. Approximately 4 Americans were killed that day, and this is significant as it shows the unrest that occurs in countries that America has played a role in militarily.