Melbourne is about 12 times bigger than Rotterdam.

Rotterdam (map shows its 22 named neighbourhoods; the area covers the whole city) is approximately 319 sq km, while Melbourne (the 27 councils of metropolitan Melbourne, without the Yarra Ranges, Cardinia, Mornington Peninsula and Nillumbik) is approximately 3,915 sq km, making Melbourne 1,126% larger than Rotterdam.
Tip: This to-scale comparison of Rotterdam vs. Melbourne uses the Mercator projection, which distorts the size of regions near the poles.
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