When did construction of the Eiffel Tower begin?

Construction of the Eiffel Tower began on January 28, 1887.

That date marks the start of work on the tower’s foundations at the Champ de Mars in Paris. The four foundations were not equally simple: the two legs nearer the Seine required compressed-air caissons so workers could excavate below the water table and reach stable ground. Foundation work was completed on June 30, 1887.

The visible iron assembly began later, on July 1, 1887, which explains why dates in accounts of the project can differ. January 28 refers to the beginning of construction overall, while July 1 refers to the start of erecting the metal structure. The tower was completed in March 1889, remarkably quickly for a project involving 18,038 separate iron pieces.

Another frequent confusion concerns the contract date. Gustave Eiffel signed the construction agreement on January 8, 1887, but physical foundation work did not begin until January 28. The tower was built for the 1889 Exposition Universelle, held to mark the centenary of the French Revolution.