Hauz Khas is a fashionable area with some of the most chic boutiques and restaurants in the city. It is also one of the most historic areas, deriving its name from the Royal Reservoir that was excavated in 1300 A.D to supply water to Alauddin Khilji's capital, Siri. The picturesque ruins comprising a madrasa (Islamic school), which was built by Feroz Shah Tuglaq, and his tomb, are stunning. The latter is a blend of Hindu and Islamic architecture. Night is an especially good time to visit this area as the lighting creates a tranquil, mellow ambience. You can round off a nocturnal ramble with dinner at "Terrace in the Sky", a roof top restaurant with great views of the ruins and the intoxicating strains of the sarod, tabla and other instruments.