Nightingale Lane in the London suburb of Clapham South, on first inspection, looks like any other average suburban street.
There's a tube station, a small collection of shops and, along one side of the street, Clapman Common, a large, green park with a pond, cricket nets and a few walking paths. There's also an old, fairly ugly rotund brick building dotted with graffiti.
But it's not on the surface where the Clapham South's most intriguing attraction lies. It's deep underground.
I meet Christopher Nix from the London Transport Museum outside a cafe and he leads me to a non-descript, modern apartment building down the street. There's a door set into the white, curved wall here that looks like a typical service entrance. Pulling out a key from his pocket, Chris unlocks the door and we step inside.
In front of us is a spiral staircase enveloping an elevator shaft, descending into darkness. Chris throws some switches and lights come on, though I still can't seen the bottom. We start down the stairs, circling around and around until we're nearly 40 metres underground – far below street level and even lower than the tube.
Chris flicks another switch and illuminates what we've come to explore: a wide tunnel extending hundreds of metres into the distance. We've arrived in the Clapham South bunker, the largest bomb shelter in the city, built with some urgency during World War II.
Conceived in 1940, approved by November 20 that year, construction began in January 1941 in order to create a shelter for 8000 Londoners. At the time, Clapham was one of the most populous areas of the city.
The bunkers were considered necessary after the Tube stations proved to be inadequate – several bombs during the Blitz managed to break through to the underground.
The vast shelters, split into several sections across two levels, were completed by 1942. By then then Blitz was over and the shelters weren't necessary. That was until 1944 when Germany being hitting Britain with unmanned V2 rockets.
Walking through the long, empty tunnels today, they seem relatively spacious. At least, that's until we enter one of the tunnels that is still set up with the bunks and living space that families sheltered in during the war.
Each area housed six bunk beds, privacy provided by a thin curtain. While some families would only come to the shelter during air raids, those whose homes were destroyed were forced to take up residence – in some cases for more than a year.
Low morale among residents was a problem in this "palace underground" as propaganda described it at the time. In order to keep spirits up, music would be piped through the speaker system and dances would be held. Food from the underground canteens wasn't rationed - if you could afford it, you could have it. Though residents were reportedly outraged at the price of a cup of tea was 2p - double what it cost on the surface.
After the war the tunnels were put to various uses – housing immigrant workers, storing documents, even a short-lived attempt to convert the space to a novelty budget hotel. The military used them as a barracks until a fire broke out and the fire brigade took more than 24 hours to bring the outbreak under control. The authorities then banned the space from being used accommodate people.
We head back to the surface, I farewell my guide and take a walk over the Clapham Common. The unassuming brick building is graffitied and grimy, with weeds growing about it. It's funny to think that, as many Londoners go about their daily business, oblivious to what the building is, an amazing part of the city's history is right under their feet.
Qantas flies to London from Sydney via Singapore, and from Melbourne via Perth. See qantas.com.au
The London Transport Museum runs tours of the Clapham South Subterranean Shelter several times a year, along with tours of several other underground facilities as part of its Hidden London tours. See ltmuseum.co.uk
FIVE MORE UNDERGROUND LONDON HIGHLIGHTS
CHURCHILL WAR ROOMS
Since Gary Oldman's Oscar-winning performance in the film The Darkest Hour, the Churchill War Rooms have had a surge in popularity. Here you can see where Prime Minister Winston Churchill and his War Cabinet planned the defence of Britain during World War II. Book your tickets in advance to take advantage of shorter queues. iwm.org.uk/visits/churchill-war-rooms
The Postal Museum's Mail Rail opened in September 2017 and lets visitors take a short ride in a miniature train through the original mail tunnels of the city. The mail service operated on this line from 1927 until 2003, carrying millions of letters a day beneath the London streets. See postalmuseum.org/discover/attractions/mail-rail-ride/
Hidden beneath Waterloo station, the Vaults are a series of art and performance spaces set within disused railway arches deep underground. There's a constantly changing collection of events and exhibitions, ranging from art installations to dance parties and jazz performances. See thevaults.london
Only discovered in the 1980s, the remains of London's only Roman amphitheatre date back to the first century. Now the site of the Guildhall Art Gallery, the surviving parts of the complex can be found in the building's basement. Entry is free. See guildhall.cityoflondon.gov.uk/art-gallery
Another of the London Transport Museum's tours takes visitors into the disused parts of Charing Cross Station – one of the city's most central stations, located beneath Trafalgar Square. Closed since 1999, the platforms are now regularly used for as locations for television and films, including 2012 James Bond movie Skyfall. ltmuseum.co.uk
The writer travelled as a guest of Qantas and Visit Britain.