ing , ▁cost ing ▁$ 5 ▁million , ▁were ▁added ▁to ▁prevent ▁such ▁an ▁event . ▁ ▁History ▁An ▁observation ▁deck ▁with ▁views ▁of ▁Boston ▁was ▁a ▁tour ist ▁att raction ▁for ▁several ▁dec ades . ▁However , ▁it ▁was ▁closed ▁after ▁the ▁September ▁ 1 1 , ▁ 2 0 0 1 , ▁terror ist ▁attacks . ▁Because ▁of ▁the ▁closure ▁of ▁the ▁John ▁Han cock ▁Tower ' s ▁observation ▁deck , ▁the ▁highest ▁observation ▁deck ▁open ▁to ▁the ▁public ▁in ▁Boston ▁is ▁in ▁the ▁Pr ud ential ▁Tower , ▁. ▁ ▁The ▁building ' s ▁own ers ▁c ite ▁security ▁as ▁the ▁reason ▁for ▁the ▁continued ▁closure . ▁They ▁have ▁r ented ▁the ▁deck ▁for ▁private ▁functions ▁and ▁have ▁expressed ▁intent ▁to ▁replace ▁it ▁with ▁more ▁office ▁space . ▁Boston ▁city ▁officials ▁cont end ▁that ▁security ▁concerns ▁are ▁mo ot , ▁since ▁most ▁similar ▁attra ctions ▁have ▁long ▁since ▁re open ed . ▁In ▁addition , ▁they ▁note ▁that ▁a ▁public ▁observation ▁deck ▁was ▁a ▁requirement ▁for ▁the ▁original ▁building ▁perm its ▁to ▁gain ▁public ▁benefit ▁from ▁the ▁high ▁tower . ▁However , ▁officials ▁have ▁not ▁been ▁able ▁to ▁locate ▁the ▁documentation ▁of ▁this ▁requirement . ▁ ▁In ▁ 2 0 0 6 , ▁Broadway ▁Part ners ▁acquired ▁Han cock ▁Place ▁for ▁$ 1 . 3 ▁billion . ▁By ▁ 2 0 0 9 , ▁they ▁had ▁default ed ▁on ▁the ▁lo ans ▁they ▁used ▁to ▁buy ▁the ▁building , ▁and ▁it ▁fell ▁into ▁forec los ure . ▁On ▁March ▁