Updated

Survivors of the Costa Concordia shipwreck and relatives of the 32 people who died are marking the first anniversary of the grounding with the unveiling of memorials to the victims, a Mass in their honor and a minute of silence to recall the exact moment that the cruise ship rammed into a reef off Tuscany.

The first event of Sunday's daylong commemoration was the return to the sea of the massive rocks that tore into the hull of the 112,000-ton ocean liner and remained embedded as the vessel capsized along with its 4,200 passengers and crew. The rocks are being returned to the reef off Giglio where they belong, along with a memorial plaque.

A land-based memorial will be unveiled after a Mass and ceremony honoring rescue crews.