Buland Darwaza or the “Gate of Magnificence”, was built in 1576 A.D. by Akbar to commemorate his victory over Gujarat. It is the main entrance to the palace at Fatehpur Sikri, a town which is 43 km from Agra, India.
The Buland Darwaza is made of red and buff sandstone, decorated by white and black marble and towers above the courtyard of the mosque.
Buland Darwaza is the highest gateway in the world and an astounding example of the Mughal architecture.

http://en.wikipedia.org/wiki/Buland_Darwaza