This is the Lego Star Wars Imperial Star Destroyer (6211) from The Empire Strikes Back.  The set comes with several minifigures including Darth Vader, Grand Moff Tarkin, and the unique Emperor Palpatine hologram. It is a huge set with 1366 pieces.

The box is sealed and is in good shape. There is some shelf wear.  The front is bowed in slightly but isn't creased or dented in.  It comes complete with all the building blocks and miscellaneous pieces to build the set seen in the pictures below.   It also comes with the original instruction manual.

This Lego Star Wars set has now been retired by Lego and is no longer available at retailers like Wal-Mart and Target.

Please contact me with any questions.