While laying the foundation for a bar at Hanoi’s Sofitel Legend Metropole Hotel in 2011, construction workers uncover an air raid shelter constructed during the past war with the US.

Every day there are two tours for visitors to the tunnel, maximum 10 people per tour.

View of foyer tunnel more than 2 metres long, 6 rooms with two entrances, one below the pool and one at the hotel centre. Many celebrities including US actress Jane Fonda and Australian diplomat Bob Devereaux have sheltered here.

Entryways to the tunnel and connecting corridors between rooms are small, narrow and dark. For convenience, the bunker has ventilation and electrical systems.

The ventilation system ensures air for 40 guests for six days.

 Australian diplomat Bob Deveraux carves his autograph on the wall back in 1975.

Construction workers find an old wine bottle, still-intact light bulbs, air ducts, graffiti all eerie echoes of a war that ends almost four decades ago.

In 2013, the bunker receives a UNESCO Asia-Pacific Heritage Award for Cultural Heritage Conservation.

Sofitel Legend Metropole is the oldest hotel in Hanoi, having opened in 1901.

Historical display area with images of guests like Charlie Chaplin, Angelina Jolie, writers Somerset Maugham and Graham Greene, actress Janes Fonda and many chiefs of state.