The milk was definitely off. I lifted the cup to my lips twice, and each time felt the sharpness of its scent deep in the back of my nose, pungent and stale, forcing me to stop shy of tasting it. The family looked at me expectantly from every seat in the ger(yurt) – the youngest little girl giggling as I winced each time I tried to drink. Finally, I willed myself to take a sip. To my surprise, it wasn’t actually that bad. “What is it?” I asked my guide Tseveen -having already learned that in Mongolia the best method was to try first and ask what was in it later. “Milk vodka – Arkhi,” she said, as l took another swig, this time tasting a faint gin-esque flavour underneath the dairy. “They make it with yak milk yoghurt – it’s about 20% alcohol.”

This was day four of my ride on the Trans-Siberian railroad – or more correctly, on the Trans-Mongolian spur of the train line – and l found myself somewhere among the grassy steppes, a couple of hours from the capital of Ulan Bator.

It’s a place that most people stop at near the end of their rail journey, as the majority go west to east. But I was doing things in reverse. Instead of starting in Moscow and descending into the spartanly populated reaches of Russia’s Siberia gradually, I’d opted to get the long flight out of the way at the start and head east to west, inching steadily back to Europe from Asia, gaining (rather than losing) time as I travelled. And now, I’d just tasted my first sip (of what would soon become many glasses) of locally made vodka – a virtually inescapable activity on this trip.

A Chinese puzzle – The previous night, I’d stayed in my own Mongolian ger, lined with sheep-wool felt, warmed by a wood-burning stove and lit by candlelight. I’d spent the evening perched at the door, watching the Milky Way stain the cloudless inky sky, while above the camp a holy ovoo (pile of sacred stones -added to by nomadic families as they trek across the steppes to ask for a safe journey) watched over the scene. It was a far cry from the modern comforts of the train carriage that had brought me here. Decked in mahogany-style cabinets and crushed crimson velvet curtains tied with golden ropes, my cabin aboard the private locomotive Tsar’s Gold was shared with just one other person (on a normal train, it would be a minimum of four).

Any worries that taking a train like this would mean aless-than-authentic experience were soon unfounded on arrival at the Chinese capital, when l was told that l would not be taking attain from Beijing at all. “What do you mean the Government has seized them?” I asked incredulously, as my guide, Freiya, gestured instead to a coach. It transpired that the official shad decided their need was greater than ours. So it was on wheels, not rails, that I began my continental crossing. My couple of days in China, roughly following the route of the train line by road, felt like trying to crack an impenetrable yet intriguing Rubik’s cube. Every time I felt like I was making progress and getting under the skin of the place, something happened to make me feel like I’d been pushed right back outside it.

This feeling started at the Juyongguan section of the Great Wall. Here the yawning brickwork sprawls up the impossibly steep hillside, stopping every few hundred metres to make way for a watchtower. It was overcast and humid when I began my short hike, making for sweaty work. But, as it rose higher, I began to leave the crowds behind and found a little section to myself, up among the trees. It felt raw and wild, but when I descended back down into the valley I found a sign that explained how most of this section of the wall had been completely restored – a modern man-made rendering of a time gone by.

In the Forbidden City, so-called because emperors (together with their eunuch officials and concubines) were once the only ones able to enter, I wandered through its courtyards as Freiya explained about the lives of those who had lived here during the Ming dynasty (1368-1644). As I looked in awe at the elaborate decor of one of the outbuildings, I noticed a locked passageway off to the side. “What’s behind there?” I asked, only to be told this particular part was out of bounds – some places it seemed were still forbidden.

Finally, on exiting, we crossed the road to Tiananmen Square, site of the in famous massacre of 1989. Our guide waxed lyrical about Chairman Mao, of the bus routes into town, of the fountain that goes off every few minutes, but nothing about the fateful events of that mass protest. When I asked her discreetly later, she said that they weren’t taught anything about it in school and internet stories were censored, so she had no idea about what happened. “I do remember one thing though,” she confessed. “A couple of weeks later, l was taking the bus with my mum and we passed the square, l looked at the tower and could see bullet holes. I asked her about them and she said, ‘It’s nothing, only shadows’.”