Distant objects can be seen with the help of 

Buland Darwaza is located in which fort

In the context of alternative sources of energy, ethanol as a viable bio-fuel can be obtained from :

Who convened the 'Congress of Vienna', 1815

Which of the following sultans adopted Persian cutoms and manners in court :

Nek Chand Saini's name is associated with which of the following gardens :