(Reuters) -The world welcomed 2024 with a mix of celebration and sombre reflection. Sydney sparkled under a shower of silver and gold fireworks commemorating the 50th anniversary of its iconic Opera House, while the mood in Gaza remained bleak, with residents more concerned with survival. In Europe, Denmark’s Queen Margrethe II announced her abdication after over half a century on the throne. Here’s how places and people around the world bid farewell to 2023 and welcomed the New Year. AUSTRALIA – Sydney hailed 2024 with a dazzling fireworks display featuring silver and gold pyrotechnics to mar…