Americans marked the 12th anniversary of the September 11 attacks on Wednesday, highlighted by somber reading of names of the almost 3000 lives lost when two planes crashed into the World Trade Center in lower Manhattan in 2001.

At a morning ceremony at the memorial plaza in New York, relatives recited the names of the people who died on that day by planned terrorist attacks by Al Qaeda operatives. Bells tolled at 8:46 a.m., the moment the first plane struck the northeast tower. At 9:03 a.m., the second airliner hit the other tower.

In addition to family members, politicians were in attendance -but did not speak- at the ceremony, including New Jersey Governor Chris Christie, former New York Governor George Pataki and New York Mayor Michael Bloomberg, in his final year in office.

One World Trade Center is now the tallest building, with its spire reaching to 1776 feet, a clearly symbolic number akin to the year of the U.S. Declaration of Independence.

The museum at 'Ground Zero' is expected to be open beneath the memorial plaza next year, which will present a broader picture of 9/11 including the experiences of survivors and first responders lost on that day.

A separate memorial was held outside Shanksville Pennsylvania, which honored the passengers and crew of United Flight 93, which struggled with the terrorists on board, and prevented it from hitting its intended target, believed to be either the White House or Capitol building. Their heroism was captured in Paul Greengrass' feature film. All 33 passengers and seven crew members were killed.