Santiago Calatrava rebuilds St Nicholas Church on Ground Zero
7 January 2015 Last updated at 00:19 GMT
Many Orthodox believers around the world celebrate Christmas today. The Orthodox Greek community in downtown Manhattan, New York, has another reason to celebrate, as the reconstruction of the church of Saint Nicholas at Ground Zero finally started last month.
After 13 years of negotiations with the region's Port Authority, work has begun on the Greek Orthodox church that will be the only non-secular building at Ground Zero. Many believe it will become one of the most visited churches in the US. It is planned to be completed by Easter 2017.
The original St Nicholas Church - a tiny townhouse standing right below the Twin Towers - was destroyed when the South Tower collapsed after the attacks of 11 September, 2001. The new church will also be a small building, made of stones extracted in Vermont and covered by a cupola that lights up from the inside at night.
The Spanish architect and engineer Santiago Calatrava, who designed the church, explains his inspiration to the BBC.
Produced by Matt Wells and Anna Bressanin