VATICAN CITY - Pope Benedict XVI has marked the start of 2008 with an appeal Tuesday for world peace.

The Catholic Church celebrates Jan. 1 as World Day of Peace, and the pope used a mid-morning Mass and a window appearance before thousands of faithful in St. Peter's Square to mark the occasion.

The pontiff called peace a `divine gift' and stressed the role of family as the foundation for it.

After leading the Mass at St. Peter's Basilica, the 80-year-old pope, dressed in ornate white and gold vestment, waved and smiled from his studio window to pilgrims gathered in the square.

Benedict returned to a theme central to his papacy, speaking of the importance of the traditional family based on the marriage between man and woman.

He said that family is the `first and irreplaceable educator of peace.' (The Associated Press) 09:23ET 01-01-08