The Eiffel Tower is a freestanding framework tower (lattice tower) located on the Champ de Mars in Paris, France. It was named after it’s Chief Designer/Engineer Alexandre Gustave Eiffel and is the most-visited paid monument in the world with several millions ascending each year.
Why was the tower built?
The plan to build a tower 300 meters high was conceived as part of preparations for the World Exhibition Fair, which would be held in 1889, to mark the celebration of the French Revolution in 1789. Over 100 designs were submitted, and the World's Fair Committee selected the conception of a 300 meter open-lattice wrought iron tower.  The two chief engineers in Eiffel's company Emile Nouguier and Maurice Koechlin, had the idea for a very tall tower in June 1884. The design was a large pylon like tower with four columns of lattice work girders, separated at the base and coming together at the top, and joined to each other by more metal girders at regular intervals. The Paris based company had by this time mastered perfectly the principle of building bridge supports. The tower project was a bold extension of this principle up to a height of 300 metres - equivalent to the symbolic figure of 1000 feet. On September 18 1884 Eiffel registered a patent "for a new configuration allowing the construction of metal supports and pylons capable of exceeding a height of 1000 feet". 
Many Parisians protested against the tower including contemporary artists who feared the construction would be the advent of structures without 'individuality' and despite the many people who feared that this huge 'object' would not fit into the architecture of Paris. 
A petition letter was signed by many angry Parisians including very notable people of the age, Jean-Louis-Ernest Meissonier (French classical painter), Charles Gounod (French Composer), Charles Garnier (French Architect), Jean-Léon Gérôme (French Painter and Sculptor), William-Adolphe Bouguereau(French Academic Painter), and Alexandre Dumas(French Author and Dramatist).
William Watson's US Government Printing Office publication of 1892 Paris Universal Exposition: Civil Engineering, Public Works, and Architecture, quoted: "And during twenty years we shall see, stretching over the entire city, still thrilling with the genius of so many centuries, we shall see stretching out like a black blot the odious shadow of the odious column built up of riveted iron plates.”
The Eiffel Tower received a permit to be allowed to stand for 20 years, and planned to be dismantled in 1909 and sold as scrap, as part of the original contest rules for designing a tower was that it could be easily demolished. The The Tower avoided to be torn down by the city of Paris as it proved valuble for communication services, therefore allowed to remain passed the expiry of the permit. 
Alexandre Gustave Eiffel was born Dec. 15, 1832 in Dijon, France. He was French Civil/Structral engineer, entrepreneur, architect specializing in metal structures.
After graduation from the College of Art and Manufacturing in 1855, Eiffel began to specialize in metal construction, particularly bridges. In 1858 he coordinated the construction of an iron bridge at Bordeaux, followed by many others, and designed the arched Gallery of Machines for the Paris Exhibition of 1867. In 1877 he bridged the Douro River at Oporto, Port, with a steel arch, which he followed with an even larger arch also a steel arch, the 162-metre span Garabit viaduct over the Truyre River in southern France, which for many years the highest bridge in the world standing at 120 m over the river. He was one of the first engineers to employ compressed-air caissons in bridge building. He designed the movable dome of the observatory at Nice and also the framework of the Statue of Liberty in New York Harbor. 
Constuction of the Eiffel Tower
Constuction of the Eiffel tower...