Location and surroundings
The Eiffel Tower is located in the west of the 7th arrondissement of downtown Paris at the northwest end of the Champ de Mars. It stands at 33 meters above sea level not far from the banks of the Seine, where there are also landing stages for excursion boats. Not far from it, southwest of the Eiffel Tower, is the elongated Île aux Cygnes (Swan Island) in the Seine. In the immediate line of sight of the structure is the École Militaire to the southeast and the Palais de Chaillot to the northwest on the opposite bank of the river above the Pont d'Iéna, widened to 35 meters in 1937. To the southeast of the École Militaire is the UNESCO headquarters in a Y-shaped building built in 1958. About three kilometers away as the crow flies in a southeasterly direction, slightly north of the exact line of sight, is the 210-meter-high Tour Montparnasse office tower. To the northeast, near the Eiffel Tower, is the Musée du quai Branly ethnological museum.
The following roads open to vehicular traffic are tangential to the tower site: to the southwest, Avenue Gustave Eiffel; to the northeast, Avenue de la Bourdonnais; to the northwest, the busy Quai Branly, from which the Pont d'Iéna branches off across the Seine; and to the southeast, Avenue de Suffren. The four streets border a wooded, park-like rectangular plot of land centered on the Eiffel Tower. Motorized traffic is not allowed to pass through.
The closest Métro Paris stops to the Eiffel Tower are Bir-Hakeim (Tour Eiffel) on line 6 and École Militaire on line 8. Line C of the Paris RER commuter rail system stops southwest of the tower at Champ de Mars - Tour Eiffel station. Several bus lines stop in the immediate vicinity of the Eiffel Tower.
Architecture
As Gustave Eiffel explained in a lecture to the Société des Ingénieurs civils on 30 March 1885, the architecture of the tower was about,
"to dispense with the large lattice bars of the vertical surfaces, which were to resist the wind. Therefore, the pier is to be given a shape such that all the forces for which the wind is responsible concentrated on the inside of the supporting uprights. [...] The tangents located at points of equal height to these supports must always meet at the point of passage of the resultant of the load exerted by the wind on the part of the pier above the points in question. [...] Before the supports unite at this high point, they seem to shoot up out of the ground, and receive their shape, as it were, by the action of the wind."
As sophisticated as the architecture is for optimizing the wind load, the basic concept of the Eiffel Tower, which has the large railway bridges made of iron trusses as its structural model, is comparatively simple. Sixteen vertically offset main struts, grouped in groups of four, rise up in an arc and are connected by the three horizontal visitor platforms. Above the second platform, the struts are united to form a pylon.
Tower base and foundation
The Eiffel Tower stands at a height of 30.5 meters above sea level at the northwestern end of the Champ de Mars (→ location). The building stands on four mighty supporting pillars made of iron trusses, each 26.08 meters wide; they transfer the entire weight to the foundation, which extends to a depth of 15 meters. The piers rest on solid masonry and are anchored to the ground with 16 rafters at a 54-degree angle. Screws 7.80 meters long connect the cast iron shoe with the substructure.
The tower construction is supported by the substructure in such a way that, depending on the wind load, it transmits a pressure of about 5 kg/cm² to the ground. This is roughly equivalent to the ground pressure exerted by an adult sitting on a chair - a comparison that Eiffel himself calculated and stated in his publication La Tour de 300 mètres.
The piers are 74.24 meters apart at the bottom, which corresponds to a total spread of the tower at the base of 124.90 meters. The floor plan of the base is square. The Eiffel Tower was constructed in such a way that each of its pillars is aligned exactly with one cardinal direction. The north and west pillars face the Seine, while the east and south pillars face the Champ de Mars. Each of the pillars contains entrances with ticket booths, staircases and elevators, which may be open in different ways depending on the crowds and the occasion. The distance between the pillars, which are connected by mighty arches, decreases with increasing height. The arches, also made of filigree-looking iron latticework, 39 metres above the ground and with a diameter of 74 metres, are purely decorative and have no load-bearing function. The passage between the pillar feet is exclusively reserved for pedestrians. On the north pillar there is a gold-coloured bust on an elongated pedestal in honour of the builder Gustave Eiffel.
Southwest of the west pier, a red brick chimney overgrown with shrubs juts out from an artificial grotto. It dates from 1887 and was used to construct the south pier during the construction phase. As part of the redesigned enclosure of the Eiffel Tower in 2018, the entire area below the piers and partially beyond was landscaped into a new garden. The area contains plants and trees, some of which predate the construction of the Eiffel Tower. Among the oldest trees is a 20-metre-high plane tree planted in 1814. The green area of approximately 2000 hectares with about 2000 shrubs and 20,000 perennial plants, such as ferns, lily of the valley or hydrangeas were newly planted to give the visitor an impression of the turn of the 20th century, which had many Parisian gardens at the time of the Belle Epoque.
· 
· 
Entrance at the east pillar
· 
Eiffel's bust on the north pillar
First floor
The first floor above the arches at a height of 57.6 metres offers space for around 3000 visitors at a time on a usable area of 4415 square metres. The restaurant 58 Tour Eiffel, a self-service restaurant and the cinema hall Cineiffel, which can also be used as an exhibition space, are located on this level. The wrap-around balcony on this level has panoramic panels on the parapet to help locate the Parisian landmarks visible from there. There is a souvenir shop and, in the south pillar, a small post office (Bureau de Poste Tour Eiffel) open daily and carrying its own postmark as a souvenir receipt. On the first floor, the 300-square-metre Gustave Eiffel Hall, which can be rented, is ideal for meetings, conferences, concerts or receptions.
At the beginning, the Eiffel Tower had elaborately glazed halls on its first floor, which were conspicuous from the outside by their arched roof structures. They contained, among other things, four restaurants with different themes. Between the north and east pillars was the Russian restaurant, now called the Gustave Eiffel Room. Between the south and west pillars was the Anglo-American bar, between the east and south pillars was the French restaurant, and between the north and west pillars was the Flemish restaurant. The latter was converted into a Dutch restaurant after the 1889 Exposition and was used as a theatre hall after 1900. All of these buildings and the historic ornaments were demolished in the course of the 1937 World's Fair and replaced by ones that were less conspicuous from the outside, in order to adapt them to the changed taste.
Along a frieze on the first floor are 72 names of eminent scientists and technicians, 18 on each side. When the tower was repainted at the beginning of the 20th century, the names disappeared; in 1986 and 1987 they were made visible again. They are mainly engineers and mathematicians who worked during the French Revolution and the first half of the 19th century. Eiffel himself made the selection of names; he was criticized for some of them. He deliberately omitted scientists with long surnames and also women who rendered outstanding services to science, for example also the important French mathematician Sophie Germain.
Second floor
At a height of 115.7 metres is the second floor with an area of 1430 square metres, which offers space for around 1600 visitors at a time. The second floor can be reached either by elevator or by one of the staircases located in the pillars; 704 steps lead up from the base to the second floor. At this level, the transfer to the elevators takes place, which continue to the top.
Here you will find the Jules Verne restaurant with 95 seats. It offers upscale gastronomy, was awarded one star by the Guide Michelin and received 16 out of a possible 20 points from Gault-Millau. The restaurant, with a floor area of 500 square metres, is slightly elevated on the south pillar at a height of 123 metres and is accessible via a separate lift. It has been under the management of chef Alain Ducasse since 2007.
There is also a snack bar and a souvenir shop on this level. The history of the Eiffel Tower is told in words and pictures in showcases specially set up for visitors.
Third floor and spire
The third and top platform is located at a height of 276.1 meters and has an area of 250 square meters. This floor is accessible to the public only via the elevators. However, there is a continuous staircase that has 1665 steps starting in the east pillar to the top. It replaced the original staircase of 1710 steps in 1983 and is lighter and less dangerous. To date (2020), the top observation deck is the fourth highest publicly accessible in Europe; the highest observation deck is currently at Oko Tower 1 in Moscow.
Above the covered platform, stairs lead up to the open-air platform, which is secured by steel grids and measures around 100 square metres. The entire area of the third floor can accommodate up to 400 people at a time. In good weather, you can see up to 80 kilometres from here. Panels point to major cities in the world in the corresponding cardinal direction and indicate the distance as the crow flies from the Eiffel Tower. In addition to a champagne bar, Eiffel's study has been faithfully restored and furnished with wax figures showing Eiffel, his daughter Claire and the American inventor Thomas Edison trying out the phonograph that Edison had brought for Eiffel as a present for the opening of the tower.
Above the visitor platform at a height of 295 meters, there is a beacon for each cardinal direction. The movement is controlled by software and can be synchronized in such a way that a continuously rotating cross is simulated with the beacons. At this height there are also several directional antennas. Above this are the dipole antennas for the radio frequencies; these are located at 291 meters and 294 meters. At the bottom of the actual antenna mast, which rises from the former lantern, there are more double dipole antennas on several floors in all directions; these are located at 299 meters and 304 meters. Above these are the UHF antennas - identifiable by the shielding, conspicuous white weather protection boxes. The top of the tower is crowned by further dipole antennas pointing in the four cardinal directions, meteorological measuring instruments and a maintenance platform.
At the top of the tower are over 120 antennas for the transmission of dozens of radio and television programmes (→ use as a transmission tower). The height of the antennas has varied over the decades. Since its opening, the actual building structure has been 300.51 metres high, reaching a total height of 312.27 metres with the lantern and flagpole at its top. Due to the additional installation of antenna platforms, the lantern can now only be seen in its upper third through the curved trusses that converge to form the antenna mast. A new antenna changed the overall height to 317.96 metres in 1991, and the 1994 rebuild at the top of the tower made it 318.70 metres tall overall. The last change in overall height was in 2000, when the tower grew to its current height of 324 metres.
Due to wind effects, the top of the tower swayed up to about 13 centimeters from its resting position during a storm in 1999. The expansion of the tower due to strong solar radiation can amount to several centimeters in height, the previous peak value of 18 centimeters was reached in the summer of 1976. According to Eiffel's calculations, the tower could even expand by up to 70 centimetres. In addition, it leans slightly towards the side facing away from the sun, as the side facing the sun expands more than the other three. At the top, this effect can add up to several centimeters.
· 
360° panoramic view of Paris from the top observation deck
