High Quality Content by WIKIPEDIA articles! The Golden Quadrilateral is a highway network connecting India`s four largest metropolises: Delhi, Mumbai, Chennai and Kolkata, thus forming a quadrilateral of sorts. Four other cities among the top ten metropolises: Bangalore, Pune, Ahmedabad, and Surat, are also served by the network. Then Prime Minister Atal Bihari Vajpayee laid the foundation stone for the project on January 6, 1999. The largest highway project in India, it is the first phase of the National Highways Development Project (NHDP), and consists of building 5,846 km (3,633 mi) four/six lane express highways at a cost of 60,000 crore (US$10.92 billion). In January 2012, India announced the four lane GQ highway network as complete. The 5,846 km (3,633 mi) of highway connects many of the major industrial, agricultural and cultural centres of India.It is the 5th longest highway in the world.