The Eiffel Tower grows up to 15 cm taller in summer
Heat makes Paris's iron landmark physically stretch — then shrink back when winter returns.
The Eiffel Tower is built mainly from puddled (wrought) iron, and like all metals, iron expands when heated. As the sun warms the structure, its atoms vibrate and push apart, lengthening every beam.
The result is measurable: the tower stands 12 to 15 centimetres (about 6 inches) taller on the hottest summer days than on a cold winter one. When temperatures drop, it contracts back down.
The effect is smaller than a naive calculation suggests. A simple sum for a 300-metre iron tower across a 100 C swing predicts roughly 36 cm of growth — but the riveted lattice and uneven solar heating (one side warms more than another) mean the real change is only about a third of that. The tower also leans slightly away from the sun as the warmed side expands.
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