Shell roofs and a great steel arch on the water.
Sydney is a harbour theatre: shell roofs and a steel arch. The Opera House is a cluster of triangular sails or shells sitting low on the water, not a tower. The Harbour Bridge is a great arch with a flat deck; in a filled silhouette the opening under the arch often remains as a rectangular bite. Behind them, the CBD is a modest tower cluster, secondary to the two icons. No other city in this set pairs a shell house with a single giant arch. If the left side looks like folded petals and the right side is a bridge with a hole under it, you are in Sydney, not Singapore’s lotus-and-boat or San Francisco’s suspension span.