A seven-layer security ring has been thrown around the VVIP enclosure on Rajpath from where Obama, President Pranab Mukherjee, Prime Minister Narendra Modi and a host of other dignitaries witnessed the grand parade.

Central Delhi has turned into a virtual fortress with nearly 40,000 personnel drawn from Delhi Police and paramilitary forces guarding every nook and corner of the area.

More than 15,000 CCTV cameras installed have been relaying every movement live to a central control room where the footage has been monitored by a joint team of Delhi Police, US Secret Services and sleuths of central security agencies.

The three-km stretch of Rajpath has over 160 CCTV cameras - with one camera installed at every 18 metres.

Pic: Pranab Mukherjee at the R-Day function