Petřín Lookout Tower of the Eiffel Tower. In contrast to the Eiffel Tower, Petřínská rozhledna has an octagonal, not square, cross-section. Further, it does not stand, as does the Eiffel Tower, on four columns of lattice steel. The whole area under its legs is covered with the entrance hall. A similarity between the Eiffel Tower and Petřínská rozhledna is the design of the lowest cross beams in the form of round bones. In 1889, members of the Club of Czech Tourists visited the world exposition in Paris and were inspired by the Eiffel Tower. They collected a sufficient amount of money and in
Gustave Eiffel Using this Eiffel definitely established that the air resistance of a body was very closely related to the square of the airspeed. He then built a laboratory on the Champ de Mars at the foot of the tower in 1905, building his first wind tunnel there in 1909. The wind tunnel was used to investigate the characteristics of the airfoil sections used by the early pioneers of aviation such as the Wright Brothers, Gabriel Voisin and Louis Blériot. Eiffel established that the lift produced by an airfoil was the result of a reduction of air pressure above the wing rather