architectural architecture Asia authority building classical-design collections Colonial color colored colors colour coloured colours columns construction decorations decorative dome domed external height heritage high historic historic-building historical history landmark Masonic-influence museum national-museum ornamental ornamentations rotunda significant Singapore stained-glass substantial tiled tiles Victorian windows zinc-fish-scaled-tiles angles appearance capping cleaning cover covered covering danger dangers ear protection edge exterior high-pressure improvement maintenance pressure pressure-cleaning renovating renovation repairs restoration restoring risks risky roof roof-area roofing rooftop safety shapes skies sky spray sunlight sunshine textures tiling tools tough water wet work workman bell-turret clock clock-tower common-corridor connected connections cupola link tower Victoria-Theatre-and-Concert-Hall-link