airy angles architecture atrium bright ceilings central circular cruise-liner cruise-ship curved curves decks ELEVATORS floating-staircase flooring floors height high interior leisure levels lifts light lines luxury multi-stories onboard open-space passengers perspectives piazza-style railing railings rails relaxation relaxing safety secure soaring space spacious staircases stairs style tourists transport travel views above aerial-balloon angled apartment-blocks backgrounds balloon below buildings cityscape colors colours condominiums flats flight-operation gondola helium helium-balloon high-rise modern motion movement multi-storey multi-story roofing roofs rooftops rooves safe scene scenery scenic secured shape shapes sights sightseeing Singapore skyline streets traffic