One hundred years from now the lens of history will provide more clarity with regard to the ramifications of the terrorist attacks on the U.S. homeland that took place Sept. 11, 2001.

But today — 10 years later — Americans know that their world changed that day, whether they were directly affected by loss of family and friends or witnessed events via TV as they unfolded that crisp autumn Tuesday morning. The horror of Sept. 11 is forever seared into our memories: Two commercial jet airliners were used as missiles by hijackers to strike the Twin Towers of New York’s World Trade Center, followed by the collapse and burning of the towers and other nearby buildings; another passenger airliner was flown into the side of the Pentagon in Arlington, Va.; and a fourth, United Airlines Flight 93, crashed in a Pennsylvania field after passengers fought the terrorists for control.

Many aspects of American life changed that day, but none is more readily apparent 10 years hence than the changes that have been forced upon commercial air travelers. Security check points at every airport are now a way of life, making it necessary for passengers to arrive at an airport at least an hour in advance of domestic flights and two hours before departure for trips outside of the United States.

Every time a passenger has to remove clothing and shoes to pass through a metal detector or surrender liquids because the containers are too large or make sure his name on his ticket precisely matches the name on his photo ID, there’s a flashback to why all of this is necessary. Then, a silent acknowledgement that all of this is preferable to being blown up in midair at the hands of terrorists plotting attacks from half a world away.

For Americans, whether traveling or attending public events in their hometowns, the real legacy of Sept. 11, 2001, is loss of some aspects of our liberty. We can no longer move about freely within our own borders or travel in other lands without fear. The horror and possibility of another 9/11 are with us.

On Sept. 11, 2011, the nation will pause to honor those who lost their lives that fateful day 10 years ago. And for the first time, the United States will issue an official medal. The U.S. Mint has been authorized to strike up to 2 million silver medals to commemorate the anniversary. The authorizing law also established the National September 11 Memorial and Museum at the World Trade Center.

A $10 surcharge per medal sold will be paid to the National September 11 Memorial and Museum to support its operations and maintenance.

The medal’s designs are emblematic of the courage, sacrifice and strength of those individuals who perished in the terrorist attacks; the bravery of those who risked their lives to save others that day; and the endurance, resilience and hope of those who survived.

Our cover story features the official medal. It also details the many private tributes created within the United States and official coins and medals issued by other nations. They are tangible links and reminders of the event and its aftermath. Each in its own way will become a part of the collective record that will survive and endure generations beyond those who witnessed and experienced 9/11. For the generations who will collect and revere them 100 years from now, they will tell the story and speak in ways different from history books and videos. They will be history that human hands can touch. ¦