The polymath thought that if a screw-like structure can rotate fast enough, it will 'drill' into the air and fly.
The design for the armoured car features the most important military requirements: reliability, portability and great firepower.
Leonardo based the design of the flapping wing on birds' wings and a faulty hypothesis.
Leonardo was not only a master artist, but also an accomplished military engineer.
The aim of this extraordinarily complex study was to mimic the different phases of the flight of birds.
Leonardo also designed a wide variety of artillery weapons.
The mechanical wing is one of the masterpieces among Leonardo's sketches related to aviation.
King Darius as well as Xerxes built pontoon bridges across the Bosphorus for the Persian army.
Types of bridges include beam-, arch-, suspension-, cantilever and truss bridges.
The Széchényi Chain Bridge, named after István Széchenyi, was the first permanent bridge across the Danube between Pest and Buda.
The suspension bridge that stretches above the strait between San Francisco Bay and the Pacific Ocean was opened in 1937.