Prime Minister Narendra Modi today inaugurated the Surat diamond exchange, a complex that has overtaken Pentagon as the world's largest office. It covers a constructed area of 6.7 million square feet and was completed in July at a cost of Rs 32 billion. The US landmark, which opened in 1943, has an area of 6.5 million square feet. The bourse comprises a state-of-the-art 'Customs Clearance House' for Import-Export; a jewellery mall for retail jewellery businesses; and a facility for international banking and safe vaults.