The Golden Quadrilateral is a highway network connecting India's four largest metropolises: Delhi, Mumbai, Chennai and Kolkata. It also connects Bangalore, Pune, Ahmedabad, and Surat. It’s the largest highway project in India, which was initiated by Atal Bihari Vajpayee. It’s the first phase of the National Highways Development Project (NHDP), and aims at building 5,846 km of four/six lane express highways.