accessory anniversary appreciation balloons birthday brown celebrate celebrating celebration celebratory circular colors colours decorated decorations decorative fiftieth fifty floating foliage fun garden gas-filled gold golden happiness happy height helium-filled high inflated leaves light plants preparation prepare prepared round shade shaded shadows shrubbery shrubs special specific thankfulness against the ceiling attached blown-up blue bright bunched colorful colourful dark dark blue helium filled interior lighter than air red reflection rounded rubber strings textures aircraft anchored balloon cable checks control controlled duty-pilot engineers fabric filled flight-operation gondola helium helium-balloon inspected inspections large limited mesh metal-cable metal-line monitored monitoring motion movement net passengers pilot piloted registered ride safe safety secure secured sights sightseeing Singapore tethered tourists views weather-limits wind-limits