The Eiffel Tower leans up to 7 inches away from the sun as one side heats and expands more than the shaded side.

The Eiffel Tower is constructed from 7,300 tons of puddled iron, a material highly sensitive to temperature changes. When the sun hits one of the four faces of the tower, the iron molecules vibrate more vigorously and take up more space. This physical process is known as thermal expansion, which causes the heated side to lengthen while the cooler side stays the same.Gustave Eiffel and his engineers accounted for this movement during the design phase in the 1880s. The maximum recorded deflection is roughly 18 centimeters, or about 7 inches, which is negligible for a structure that stands 330 meters tall. This phenomenon is most pronounced on clear, hot days when the temperature differential between the sunny and shaded sides is greatest.In addition to this daily tilt, the tower's height can also fluctuate. In extreme summer heat, the entire structure can grow up to 15 centimeters taller. Conversely, in the winter, the iron contracts and the tower shrinks by several inches. These movements are monitored by the Société d'Exploitation de la Tour Eiffel to ensure the structural integrity remains intact over time.