By Declan Harte

Stunning south-east Asia is both firmly rooted in its turbulent past and boldly stepping into a vibrant future.

On a three-week, whistle-stop tour from Bangkok in Thailand to Hanoi in Vietnam (via Cambodia), my partner and I sampled a wild serving of sun, spice and history.

More than 6,000 miles from our South Wales home, bustling Bangkok was our welcome to the colourful Indochina peninsula.

A traditional Thai massage helped me forget my 12-hour journey from Heathrow to the Bangkok Centre Hotel.

Having had most of the jet-lag twisted and squeezed out of my weary muscles by an expert masseuse, we headed to the city's hectic Chinatown district for a meal of spicy noodles from one of the many street-food stands.

The following morning, we strolled through city heat to the Wat Pho temple complex and Grand Palace. Striking photo opportunities are in abundance, but so are the other tourists, so get there early and start snapping.

Saying goodbye to Thailand, a bus took us to the busy Cambodia border crossing. The resort town of Siem Reap, in north-west Cambodia, is a popular gateway to the nearby ancient ruins of Angkor.

We checked into the airy Bayon Leaf hotel, before organising a minibus trip to majestic Angkor Wat - the world's largest religious building - at sunrise the next morning and set our alarms for 4.30am. Hordes of tourists armed with cameras jostled for position in darkness outside the world wonder to get that all-important sunrise shot. We were not lucky enough to get a clear morning, so the camera-shy sun was obscured by a blanket of cloud. However as day broke, the vast structure was still a staggering sight to behold as it revealed itself.

The nearby Ta Prohm temple exceeded it in terms of pure spectacle. Known as the "Tomb Raider temple" after being used as the location for the 2001 Angelina Jolie film, it is wrapped in vast tentacle-like vines and it appears to be getting swallowed up by the jungle.

The unique Phare circus is performed in a large tent nightly on the edge of Siem Reap and should not be missed. This social enterprise gives street youths from the poorest areas a way out of poverty by teaching them acrobatics, music, dance, clowning and thrilling stunt work. We got close to the action with ground-level, front-row seats. The audience gasped as a traditional Cambodian folk tale of love, conflict and magic was played out with flames, fury and a huge catapult that launched performers 20 feet into the air.

The show's operations manager Senleaphea Mam explained how the project helps turn young lives around. She said: “They were maybe picking up rubbish in the street when we first approached them as young children. In this school they learn reading, writing and English, as well as juggling dancing and music.”

Officially a third-world country, Cambodia is still living in the shadow of past genocide under the brutal Khymer Rouge party. To better explore the country's dark past, we took a guided tour of the infamous Killing Fields, accessible from the capital Phnom Penh. An estimated 1.7 million people were sent to their deaths between 1975 and 1979, when Pol Pot's Khymer Rouge ruled Cambodia. The skulls of many who were beaten to death, after being forced to dig their own graves, can still be seen at the Killing Fields today.

One of the few to survive arrest, Chum Manh, 85, was on hand to explain the brutal torture he received at Tuol Sleng interrogation prison. Under suspicion of working with the CIA, he was taken from his family and forced to endure savage beatings and electrocution.

He told me: "When I first came back and saw the prison I had to cry. However it is great that so many visit now and learn the truth about what happened."

We also sampled Cambodia's infamous dish of fried Tarantula at Phnom Penh's sprawling Russian Market. Less-adventurous diners can grab a table at the city's plush Bopha Phnom Penh Restaurant, where we savoured water buffalo and fish amok while taking in the evening riverside view.

A country still getting back on its feet, the Kingdom of Cambodia has no regular rail network, so train travel was out of the question and we crossed the country by bus. Our next hop-off was the seaside town Sihanoukville on the south coast. Those with a Celtic complexion need to slather on the sun cream here before basking on the unspoilt Otres beach, where powerful rays beam down and temperatures approach 40C.

Next, we crossed the border into Vietnam, the final nation of three-country jaunt.

Our exploration began with a junk-boat cruise through a floating market on the Mekong River.

Then onto Vietnam's largest metropolis, Ho Chi Minh City. Known for many years as Saigon, it is home to 10 million people and 5.5 million motorbikes - one buzzing bike for every two residents. We made our way to the city's historic Grand Palace and War Museum, where US tanks and guns can be seen, alongside shocking photos showing the effects of napalm and American chemical weapons such as Agent Orange.

This was followed by a meal at eatery Pho 2000, which hosted Bill Clinton in 1995, when he was the fist US president to visit Vietnam since the war. I opted for pho bo (a tasty beef noodle broth) and impressed myself with my growing chopstick skills.

History buffs who aren't afraid to get their hands dirty should pencil in a trip to the wartime Cu Chi Tunnels, accessible by bus from Ho Chi Minh City. Visitors can crawl through the actual tunnels used by the Viet Cong to transport weapons and outfox US troops. There is also a shooting range where trigger-happy tourists can fire actual Russian AK-47s, the favoured artillery of the Viet Cong.

Lowering myself into the tunnel, with the sound of the nearby gunfire clattering in my ears, I crawled on all fours into the darkness. Determined guerilla fighters endured rats, poisonous centipedes and scorpions when they spent months underground in cramped conditions and disease was rife. Now, the tunnels have been widened slightly for the tourists, but it was still a claustrophobic crawl and I was grateful to finally spy daylight at the end.

Vietnam is pulling away from it's war-torn past and now enjoys a booming economy. It is currently the world's number-one exporter of rice - as well as number two for coffee.

Unlike Cambodia, the nation is covered by a modern rail network, so we used overnight sleeper trains to get from the south to the north.

We rolled into historic Hoi An, 500 miles from Ho Chi Minh City, and were welcomed by the grand traditional architecture of the riverside town. After enjoying the regional delicacy of white rose dumplings, we hired bicycles to explore some of the countryside of central Vietnam. We put thoughts of the noisy and congested cities far behind us as we peacefully pedalled past paddy fields, where friendly farm workers in pointed conical hats waved to us while tending crops.

Our next overnight train delivered us to our final city: Vietnam's capital Hanoi. A mass of motorbikes swarmed the streets of the modern metropolis, while traders loudly bartered over everything from gourmet coffee beans to popular electrical items.

As ever with Vietnam however, the past was never far away and many of our final activities were flavoured with history. The Ho Chi Minh mausoleum is a place of pilgrimage for many Vietnamese and was busy when we arrived. The former leader and national icon can be viewed lying in an embalmed state (in the tradition of Lenin, Stalin and Mao) at the heavily-guarded building.

A tour of the former Hoa La Prison – dubbed the “Hanoi Hilton” by American POWs – provided a fascinating glimpse into a brutal past. Then, going back a few hundred years, we visited courtyards of the 11th century Temple of Literature. Large groups of rising university students in colourful gowns also gathered at the site for a day of graduation ceremonies. It seems the enchanting region will continue to grow and leave its mark on all who visit for many more years to come.