BOSTON (CBS) – The hole in the ground that was once Filene’s Basement is no more after workers began burying the space under the largest pour of concrete in the city’s history.

The work being done by Suffolk Construction began early Saturday morning is an important milestone in the construction of the $689 million, 1.4 million-square-foot Millennium Tower/Burnham Building development in Downtown Crossing at the former site of Filene’s Department Store.

WBZ NewsRadio 1030’s Kim Tunnicliffe reports