Melbourne is about 39 times bigger than Barcelona.

Barcelona is approximately 101 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 3,765% larger than Barcelona.
Tip: This to-scale comparison of Barcelona vs. Melbourne uses the Mercator projection, which distorts the size of regions near the poles.
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