Rebuilding begins at Ground Zero

Rebuilding begins at Ground Zero---A ceremony has been held in New York to mark the start of building on the skyscraper which will replace the destroyed World Trade Center.
A 20-ton block of granite was laid as a cornerstone of the Freedom Tower, which is planned to be the tallest building in the world at 1,776 feet (541m).
Its height reflects the date of US independence, while the ceremony was held on Independence Day. (BBC)