Christmas Island is about 102 times smaller than Montenegro.

Montenegro is approximately 13,812 sq km, while Christmas Island is approximately 135 sq km, making Christmas Island 0.98% the size of Montenegro. Meanwhile, the population of Montenegro is ~604,966 people (602,761 fewer people live in Christmas Island).
Tip: This to-scale comparison of Montenegro vs. Christmas Island uses the Mercator projection, which distorts the size of regions near the poles.
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