Overnight Thursday, construction crews put up a fence along the back (Dean Street) of Barclays Center, signaling the beginning of construction on the first of three towers at the eastern end of the arena. The ground breaking for the first tower is scheduled for December 18. The 32-story apartment tower is the first of three modular buildings, the world's tallest, to be built at the site. Another 13 towers will be constructed on the cleared area further east across Dean.

According to Forest City Ratner, the each building should take 20 months to build. Once one tower is done, there will be a six-to-nine month before ground-breaking for the next one. The three towers at the back of Barclays Center may well take as long as six years.

• Dean Street Squeeze begins near Flatbush Avenue; street, sidewalk narrow for B2 construction - Norman Oder - Atlantic Yards Report