London is about 15 times bigger than Tempe.

Tempe (map shows its 64 named neighbourhoods; the area covers the whole city) is approximately 104 sq km, while London (including the 32 boroughs of greater London) is approximately 1,572 sq km, making London 1,418% larger than Tempe.
Tip: This to-scale comparison of Tempe vs. London uses the Mercator projection, which distorts the size of regions near the poles.
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