If you are thinking of going on the Tunnel Rats Book Tour – or any other trip in Vietnam – there’s a fairly recent addition to the tourist trail which is definitely worth a detour.

We are used to going underground when we get to our former foes’ labyrinthine tunnels at Cu Chi just to the North of Ho Chi Minh City. But there’s a whole new subterranean experience awaiting intrepid travellers who venture further north … and one where you’ll be looking up in wonder and amazement, rather than scrabbling round on your hands and knees.

The Paradise Caves in Phong Nha-Ke Bang National Park, are a UNESCO World Heritage Site 60 km northwest of Dong Hoi city, roughly in the centre of the country,  near the west branch of Ho Chi Minh Highway in Quang Binh Province, where Vietnam is at its narrowest and it’s only a couple of hours driving from the coast to the Laos border.

The Paradise Caves or Dong Thien Duong, to give them their local name, are the longest cave system in Asia at 31 Km and were discovered by a local man as recently as 2005, then explored by the British Cave Research Association shortly thereafter (click on the pics to see the full gallery).

The largest cave in the long chain reaches up to 100 m high and 150 m wide but it’s not even the biggest in the area. Further into Phong Nha-Ke Bang National Park, which straddles the Laos border, there’s Hang Son Doong, now recognised as the largest cave in the world.

The Mountain River Cave, to give it its English name, is more than 200m wide, 150m high, and almost 10 km long, making it twice as large as Deer Cave in Malaysia (which was previously thought to be the world’s biggest).

There are believed to be between 150 and 300 caves in the area but the new kid on the block, the Paradise Caves, is possibly both the most easily accessible and rewarding. The caves have only been opened to tourists since September 2010 and the  stalactites and stalagmites are quite spectacular and all surprisingly tastefully lit along a 1km wooden walkway.

After a short drive into the mountains, you disembark at the gates to mount electric carts that whisk you up the last steep incline to the cave’s entrance, then you have a fairly strenuous climb of 500+ steps to the narrow entrance in the side of the cliff.

The sight that greets you is breathtaking; you are closer to the roof than the floor of the caves and the dim lighting is just enough to let you see the massive extent of this underground wonderland. Another 180 steps down gets you to the start of the walkway and it gets a lot easier from that point as the broad timber boardwalk winds through ancient rock formations that often look remarkably like grotesque statues.

The lighting is not to some tastes, a little overdone for the purists but nothing like as garish as other caves, especially in Asia.  You are free to take your own time (depending on whether you are with a tour or not) with the added multicultural smorgasbord of languages as you pass tour groups, each listening to descriptions in their own tongue, provided by guides with ‘Madonna’ microphones and little speakers attached to their belts.

Even so, this is an incredibly peaceful place and you can always find a corner for some quiet contemplation of the wonders stretching in every direction around you. For even better pictures than my amateur efforts, have a look at Billy Law’s pic’s here.  Billy, a former Masterchef contestant, as well as a professional photographer, was one of the media group on this Vietnam Airlines sponsored trip.

Back to the caves. The Mountain River Cave or Hang Son Doong, is a very different experience that requires a six hour trek through leach-infested jungle before you even get to the hidden cave entrance.  You can read a National Geographic account of a recent expedition HERE.
A much more leisurely expedition is to the Phong Nha Cave where you go for about 1500m along its underground river on little boats that take ten tourists at a time. With new caves being discovered every year, you can find a caving adventure that’s as challenging (or not) as you want.
The perfect base for your adventures is the seaside town of Dong Hoi with its beaches and five-star Sun Spa resort.  The Sun Spa is a genuine five-star resort, on a par with the more laid-back hotels of, say, Thailand or Bali.  And by laid-back I mean they are cool, quiet and comfortable and not over-run by binge-drinking Aussies and sunblistered Eurotrash jostling for pool beds and a space at the bar.

Like just about every half-decent hotel in Vietnam, there is free and reliable wi-fi in the room, the beds are spacious, clean and comfortable and the  flaws are quirky rather than catastrophic (the bath didn’t quite reach the wall so every shower was a flood).

One of the ironies of eating in Vietnamese hotels is that, despite the country having one of the most interesting and healthiest cuisines on the planet, many establishments feel compelled to show how good they are at home cooking – home being where you came from, rather than where you are.

But if you tell them in advance that you want real Vietnamese food, get ready for a mixture to flavours and textures that will take your tastebuds   on an amazing trip from which they will never want to return.

However, if you grab a bike from the hotel and cycle ten minutes into town you can find a lively food market in one direction (live eels or frogs anyone?) and, the other way, a riverside beer garden selling freshly grilled squid.

Having been on the edge of the demilitarized zone, Dong Hoi took a fair old pounding during the war and there’s a burnt-out church that stands as a monument to man’s inhumanity to man.  But, spectacular beaches aside, it’s the caves that are the big attraction – big enough to put the Sun Spa resort and its tours on your itinerary.