Granada is most famous for the Alhambra, the palace built during the period when Spain was occupied by the Moors and still towers above the city today.
The Alhambra itself dates from 1228, not long before the Spainish recaptured the area in 1238. Granada remained a state of the Christian kingdom for the next 250 years, gradually shrinking over that time. By the time of the voyages to America in 1492 it only controlled a small territory on the coast and the last Muslim leader, Boabdil, surrendered complete control to Ferdinand and Isabella.
With such a history, the arabic influence is strong and the Christian influence in terms of cathedrals and the like date from the 1500s. The Alhambra itself is the major attraction, but other substantial places include the Palace of Charles V, Granada's Cathedral, Capilla Real (with the tombs of Isabella and Ferdinand), El Albayzín (the old Arab quarter), the Charterhouse, and many others.
Granada airport (GRX) is served by discount airlines plus a number of connecting flights from Madrid and Barcelona. It's close enough to fly to Malaga and get a bus which gives you a much wider range of flight options.
The city is well connected to the Spanish rail network. It's around five hours by train from Madrid.
