More than 20 million people live in Beijing. Imagine the equivalent of the entire population of Australia in one city.
Long gone are the swarms of bicycles, cars now choke the streets and elevated expressways. Beijing's metro system would be good for a population half its actual size as platforms are crowded and trains arrive already full.
Beijingers are tidy folk and don't drop much litter - but many still love a good spit. The harsh anti-spitting penalties introduced during the Olympics have worn off so it was good to see the "spit-mopping" ladies swabbing the passageways.
It's not the regimented communist city I imagined, although Big Brother does block web access.
The Beijing 798 Art Zone was a great surprise - hundreds of galleries sprawling through disused factories with huge art installations, street musicians, market stalls, street cafes, bars and little restaurants.
The Forbidden City and the Great Wall are spectacular but it's difficult to find a time when they are not crowded.
Getting a train ticket wasn't easy. Tickets sell out quickly, stations are packed and English speaking is rare.
As the only European on the train, I attracted many sideways glances but had a four-berth soft-sleeper cabin to myself. There was no menu or cutlery in the restaurant car but I managed an excellent spicy chicken with chopsticks. With three beers, the total cost was $6.
Women in coolie hats and water buffalo could be seen working paddy fields edged with bamboo.
Further south, the landscape was straight from a Chinese painting - jagged mist- shrouded mountains in the distance and mysterious tree-clad pinnacles of rock. A vision of old-world China - but with the occasional grubby tenement block and factory chimney belching smoke.
The train terminates at the border town of Dong Dang and after going through the Vietnamese border control I board a grubby Vietnamese train.
Vietnam is a sea change of life and culture. The French colonial influence is very evident and the French Quarter is a maze of streets and alleyways, infuriatingly choked by motorcycles.
Walking is a nightmare, something only visitors do. Locals ride motorbikes or catch the motorbike taxis which haunt every corner. Pavements are cluttered with motorcycles, kitchens, diners, workshops and street traders; I warmed to Hanoi after a few days but still caught the Reunification Express south.
Hue, the ancient royal capital and the heart of Vietnamese history and culture, was a relief from the bedlam of Hanoi. Like communist China, Vietnam has discovered that imperial history attracts visitors.
The walled Citadel, north of the Perfume River, was a grand building but it still bears the scars of the heavy fighting in 1968.
The nearby Thien Mu Pagoda had a gory surprise - the Austin Westminster car which Buddhist monk Thich Quang Duc drove to the then Saigon in 1963 before setting himself on fire as a defiant act against the repressive South Vietnamese regime of Ngo Dinh Diem.
Emperor Tu Duc's tomb is much more than a tomb - it was his royal country retreat. Despite having more than a hundred wives and concubines he had no children so built this as his own epitaph. Today's crumbling ruins of steps, gateways, terraces, canals, lotus lakes and waterside pavilions are idyllic but rather haunting.
Further south is the UNESCO World Heritage town of Hoi An but with no railway I had to take a bus. Fabulously laid-back, the old town is full of traditional character with no modern buildings so there is a real sense of old Vietnam.
The waterfront is a hive of activity with boat trips, places to just sit and watch life unfold and beer for 20 cents a glass!
At one end there's a street market, at the other is the famous Japanese Bridge and in between the charming old Chinese and French colonial houses, now converted into coffee shops, bars and restaurants serving Vietnamese food alongside pasta and pizza.
I caught the overnight train from Da Nang to Saigon. It was packed and when I opened the door of my cabin a Vietnamese family looked horrified as I squeezed in and climbed on to the top bunk. All attempts at communication disintegrated into confusion but we swapped food and smiled.
Passing through a wide valley with mountains on each side, people were ploughing paddy fields with water buffalo and huge flocks of egrets and white ducks looked like drifts of snow.
Ho Chi Minh station was the usual bunfight of taxi-bike operators and taxi touts. I wait out the scrum with an overpriced coffee and then take a surprisingly cheap taxi to my hotel.
Although Ho Chi Minh City is twice the size of Hanoi, it's not the capital even though it acts the part. It's Vietnam's hub for international commerce, shipping, luxury hotels, vast shopping malls and at night it's a bright and glitzy party town.
The Street Walking Tour I booked with Travel IndoChina was a Godsend. You have to forget everything your mother taught you about road safety and re-learn the Vietnamese way. Except on a few major thoroughfares, the pavements are cluttered with food stalls or parked bikes and are so uneven it's like tramping across a ploughed field.
The city's six million motorbikes go where they like when they like - they jump red lights, ride along pavements, go the wrong way up traffic lanes and even go the opposite way around roundabouts. Vehicles just barrel on through junctions, the only rule is to give way to anything bigger and faster than you.
There are a host of iconic buildings - the Continental hotel where Graham Green drafted The Quiet American, the Rex hotel where the Americans gave their daily war briefings and the rooftop where the last helicopters evacuated people after the fall of the city.
Its impossible to ignore the war. There's the city centre museum but more impressive are the 250km network of tunnels at Cu Chi, an unbelievable feat of bucket-and- spade engineering and the ultimate destination of the Ho Chin Minh trail.
It's become a bit of a theme park but is a key part of Vietnam's history and one they are very proud of. The Americans gassed, flooded, bombed and even sent in dogs but the VC survived and they think of Cu Chi like the Brits think of the Battle of Britain.
I intended to travel up the Mekong to Phnom Penh in Cambodia but only expensive cruises now ply that route so I had to take another bus. For $15 a taxi took me to the bus station and six hours later I arrived in Phnom Penh.
With a visa from home, the border crossing was simple although they did take fingerprints, an iris scan and quarantine took my temperature.
Money changers try to sell you riel but don't bother as US dollars are the universal currency in Cambodia and begging starts at the border and is relentless.
After slumming it in Vietnam, I checked into Raffles Hotel Le Royal for a touch of luxury.
Phnom Penh is a relatively new city and little existed before 1863. Compared to Vietnam, the streets are pleasant - they're busy, just not insanely frantic. There is no public transport, taxis are rare, motorbike taxis (motodup) are ubiquitous but the tuktuk is king of the road.
The Central Market is amazing, more reminiscent of a great yellow domed mosque than a market place. The Royal Palace is very grand, full of multi-tiered Khmer buildings, but a more important place to visit is Toul Sleng Genocide museum, or S-21 as the Khmer Rouge called Toul Svay Prey High School.
It became the Pol Pot regime's sadistic torture centre from 1975-78. Just like the nazis in Europe, the guards kept meticulous records of their victims, including death counts roughly scratched on walls.
Nothing is held back. The torture equipment is still there, horrific photographs are on display but worst of all is the realisation that previous neighbours and friends had so easily become monsters. What a horrific and chilling facet of human nature.
Floods ended my second Mekong attempt so it was another six-hour bus trip to Siem Reap - gateway to Angkor Archaeological Park. Siem Reap is a charming provincial town having grown from a few riverside villages into a thriving town of stylish French colonial architecture.
I enjoyed Raffles Phnom Penh so much I checked into Raffles Grand Hotel d'Angkor, the oldest and best hotel in town, where I had my best Khmer food. It is similar to Thai food but more fragrant and less spicy.
Angkor Wat was awe- inspiring, one of those rare world icons which exceeds all expectations. There is a real sense of exploration - climbing broken steps, peering through dark doorways and investigating meandering corridors.
The Bayon temple was as extraordinary as TV images promised. The giant enigmatic faces looking to all corners of the Khmer kingdom are as breathtaking as ever.
But the temple of Ta Prohm was the most atmospheric, shrouded in dense jungle and invoking all the romance of a lost city. Overhead parrots quawk, baboons screech and everywhere butterflies and dragonflies fill the air. Gigantic roots of strangler fig, banyan and kapok trees crawl like snakes over roofs, walls and terraces, ripping them apart and becoming part of the buildings' fabric.
- fact file *
·Ho Chi Minh City walking & Cu Chi tunnel tours can be booked with Travel IndoChina. travelindochina.com.au
·Rooms at the Raffles Hotel Le Royal in Phnom Penh are from $237 per night. raffles.com/phnom-penh
·Raffles Grand Hotel d'Angkor has rooms from $270 per night including champagne breakfast. raffles.com/siem-reap
·Rail holiday specialists Railbookers have a six-night Reunification Express itinerary following my Vietnam route - Ho Chi Minh, Hoi An, Hue and Hanoi, starting at $995 including private tours and four nights in 5-star hotels with breakfast. railbookers.com.au and 1300 938 534