Ulm is about 3 times smaller than Atlanta.

Atlanta (map shows its 114 named neighbourhoods; the area covers the whole city) is approximately 350 sq km, while Ulm (map shows its 55 named neighbourhoods; the area covers the whole city) is approximately 119 sq km, making Ulm 33.86% the size of Atlanta.
Tip: This to-scale comparison of Atlanta vs. Ulm uses the Mercator projection, which distorts the size of regions near the poles.
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