The visitor to Delhi might be lucky enough to get his first glimpse of the city&rsquos architectural heritage out of the window of a plane or train. The rugged outline of Tughlakabad fort (built 1320-24) can sometimes be seen from the air, as can Firoz Shah&rsquos madrasa at Hauz Khas, built a few decades later, the domes of which can be seen nestling among the greenery of the Hauz Khas park. Even more exciting is a glimpse of the strange profile of the late 12th-century Qutb Minar as the plane comes in to land.