
From the highest observation deck in the world, on the Shanghai Tower's 126th floor, to the One Liberty Place observation deck in Philadelphia on the 57th floor, the spectacular views from most urban observation decks can only be seen and photographed through glass.
Dealing with glass reflections at observation decks is the main problem for photographers there. It comes from the deck's internal lighting, plus interior surfaces reflecting sunlight on to the glass. Additional problems can come from visitor restrictions and maintenance.