The metal structure of the Eiffel Tower weighs 7,300 tonnes while the entire structure including non-metal components is approximately 10,000 tonnes. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7 in) because of thermal expansion of the metal on the side facing the sun. The tower also sways
6–7 cm (2–3 in) in the wind.[3] As demonstration of the economy of design, if the 7300 tonnes of the metal structure were melted down it would fill the 125 meter square base
to a depth of only 6 cm (2.36 in), assuming a density of
the metal to be 7.8 tonnes per cubic meter. The tower
has a mass less than the mass of the air contained in
a cylinder of the same dimensions,[7] that is 324
meters high and 88.3 meters in radius. The weight
of the tower is 10,100 tonnes compared to 10,265
tonnes of air.

Maintenance of the tower includes applying 50 to 60 tonnes of paint every seven years to protect it from rust. In order to maintain a uniform     appearance to an observer on the ground, three separate colors of         paint are used on the tower, with the darkest on the bottom and the         lightest at the top. On occasion the colour of the paint is changed; the         tower is currently painted a shade of brownish-grey.[8] On the first         floor there are interactive consoles hosting a poll for the colour to                 use for a future session of painting. The co-architects of the Eiffel         Tower are Emile Nouguier, Maurice Koechlin and Stephen                         Sauvestre.[9]

The first and second levels are accessible by stairways and lifts. A ticket booth at the
south tower base sells tickets to access
 the stairs which begin at that location.
At the first platform the stairs continue
up from the east tower and the
third level summit is only
accessible by lift.

Since the beginning of the 20th century, the tower has been         used for radio transmission. Until the 1950s, an                         occasionally modified set of antenna wires ran from                 the summit to anchors on the Avenue de Suffren                 and Champ de Mars.