Through contacts in Sal Maroni's organization and corrupt officers in the Gotham City Police Department, the Joker organized the kidnapping of Rachel Dawes and had her kept in the warehouse. Rigging it to explode, Joker planned to test Batman on whether he'd save Harvey or Rachel.
Whilst in custody, Joker gave the address as the place where Harvey Dent was being kept. Believing the clown to have told them the truth, Gordon mobilized the GCPD to get to the location before it exploded. However, Batman discovered the ruse when he arrived at Dent's location. With Gordon not making it in time, Rachel died when the bombs detonated. Batman later visited the location, where he retrieved Dent's coin from the rubble.
After becoming the murderous vigilante Two-Face, Dent kept Gordon's family at the location and forced him to come to the warehouse, planning on executing them for him not making to Rachel in time. Holding his son hostage, Dent was confronted by Batman. During the confrontation, Dent decided his and Batman's guilt in Rachel's death (finding the Dark Knight guilty and himself innocent). Before he could find out Gordon's guilt (planning to kill his son if guilty), Dent was tacked off the rooftop by Batman before he could find out. This caused Two-Face to fall to his death, though Batman was able to rescue the child. Over Dent's body, Batman and Gordon decided to place the blame on him for both Dent's death and the murders the District Attorney had committed as Two-Face.
Behind the scenes
The name "250 52nd street" is very possible to be reflected upon the number "2" and "50/50" which are used together. The street is pronounced "two-fifty-fifty-second street". This is an interesting coincidence, as Harvey Dent becomes Two-Face after the events here.