The annual Sept. 11 commemoration ceremony has changed little over the years. But so much around it has.

The museum now sits open at the site of the tragedy.

The fences have come down around the memorial plaza, more fully integrating it into Manhattan's streets.

A new mayor is in office, Bill de Blasio, one far less linked to the attacks and their aftermath than his predecessors.

And One World Trade Center is nearly complete and set to open later this year, perhaps signaling that page in the city's history may be turning.

For some who lost loved ones in the terror attacks, the change is a sign of progress.

For others, it threatens to interfere with their grief.