Knowledge Base
Buildings, structures, design, materials, and surprising details about the spaces people create.
Heat causes the Eiffel Tower's iron to expand, and sunlight warms its sides unevenly. During a clear day, the top can trace a roughly circular path measuring about 15 centimeters, or 6 inches, in diameter as the Sun moves across the sky.
Inside Rome's Pantheon, the height of the building is equal to the diameter of its concrete dome—both just over 43 meters. An opening in the dome called the oculus measures 8.92 meters across and provides the interior's only natural light.