Today, the nation takes time to remember a day that must never be forgotten - 9/11 - with many still wondering what truly happened.

Observances took place all over the country, most notably Washington, D.C., Pennsylvania and of course, New York's Ground Zero, according to CNN.

President Obama was on hand for a moment of silence outside the White House, remembering the thousands of American lives that were taken during America's deadliest terrorist attack.

A ceremony was held at the the National September 11 Memorial Plaza where relatives of World Trade Center victims gathered in remembrance. More than 1,000 people were gathered near the tragic site, according to the Inquisitir.

And in Pennsylvania, names were read aloud of the victims who crashed in a field after trying to take control of a terrorist-controlled plane.

Now, 14 years after the massive tragedy, people are still asking questions about the attack and how something so awful could happen.

"Truthers," people who believe that there is a conspiracy or cover-up regarding 9/11, still search for more reasonable explanations for the attacks.

There is a substantial following of truth seekers in the U.S., with some celebrities like Mark Ruffalo and Rosie O'Donnell being among those who believe there is more to 9/11 than what the public is told, according to the International Business Times.

The 9/11 tragedy - and the almost endless theories about the horrific events - have changed people's lives.