In the middle of the Salar de Uyuni, I'd met a traveller from Manchester who said that by far the most exciting thing he'd done in South America was cycling from La Paz to Coroico. I like mountain biking a lot, and this ride, which would actually involve mountains, sounded like a lot of fun. So when I arrived in La Paz on Boxing Day my first priority was to book onto a tour.
The ride doesn't actually start in La Paz, which is a mere 3600 metres above sea level. It starts at La Cumbre, a pass high, high in the Andes at 4700m above sea level. Coroico is 64km away horizontally, and three and a half kilometres vertically. It's downhill all the way, but the catch is that the road is just a narrow ledge cut into breathtakingly steep mountainsides. Sadly, it's a road with a reputation for tragedy - buses and trucks fall with horrible frequency into the valley, and it is frequently described as the most dangerous road in the world.
So I was slightly nervous when I got up at 6am to get ready for the tour. I was also extremely tired, having made a tactical error by choosing a room in my hostel which had a balcony overlooking Calle Sagarnaga. The balcony was nice but Calle Sagarnaga does not sleep, and neither did I thanks to the continuous rumbling of traffic and noise of people throughout the night. I got a strong coffee and then went to the offices of the bike company. We drove up to La Cumbre, where clouds whipped by in a bitterly cold wind, and snow lay on the ground. Here we had a safety briefing, and we all rode around a little bit to get used to our bikes. And then, it was time to set off.
The route began on smooth, well-paved roads, which meant that we could go very fast. However, it was below freezing, and before long I couldn't feel my fingers and my eyes were watering so much I could hardly see. Things took a turn for the worse the very first time I had to brake at all hard, when my bike started fishtailing and before I knew what was happening I was crashing down onto the tarmac. I was pretty shaken and my right shoulder had taken a hard knock, but I was OK to carry on. But now I lacked confidence in my bike, and found myself propping up the rear of the group, with even a timid Swiss girl easily able to outpace me. This was very disappointing for me.
We descended through a police checkpoint. Coroico lies in the Yungas, a region of Bolivia which produces large quantities of coca leaf. The leaf itself is used widely for chewing and brewing, as it has been for centuries, but it can also be used to produce cocaine, of course, and so movements of large amounts of coca leaf are monitored intensively. We passed through and carried on down. Soon we reached a short uphill section, which would have been a great workout as we were still only just under 4000m above sea level. I was hoping to win the informal contest, having been so slow on the downhill, but as soon as I put the power down, my entire rear derailleur collapsed into the rear wheel with a horrific crunch. It was game over for my bike.
Luckily it was not game over for my ride. The company had spares, which were in a support vehicle following us. They drove me to the top of the uphill section, past my fellow cyclists, and prepared a new bike for me. I was genuinely disappointed not to have done the uphill section, but no-one believed me when I said this. The new bike instantly felt enormously better, and when we set off again I was able to lead the pack. Soon we were at the end of the tarmac and the start of the tricky part of the road, and here we split into two groups. I decided to try the faster group, and this proved to be the right decision.
It was the rainy season, and this part of the road was pretty rutted and muddy. Occasionally waterfalls fell right onto it. But the ride was becoming extremely good fun, as we twisted and turned through breathtaking mountain scenery, all the while with dizzy drops just a few feet to our left. We stopped fairly frequently for snack breaks and equipment tuning - brakes needed constant checking, as the consequence of a failure didn't bear thinking about. The lower we got, the thicker the air got and the faster we went. I had my own personal favourite moment of the tour on this muddy section when the guide overtook a bus just before a bend. I decided to follow, passing the bus at speed on the outside, just a few inches from the edge of the road, with my shoulder still killing me from my earlier tumble.
As we got lower, the temperature rose and it became humid. We were now in the coca, coffee and banana-growing regions and the air smelt earthy and fertile. The road was dusty now, but having spent the last two weeks more than 3000m above sea level, I could breathe through my nose and still cycle as hard as I could. I was amazed at how acclimatised I was, and understood why athletes train so much at altitude. Now I was really hitting my stride, and the guide and I led the pack by a long way.
Eventually we saw Coroico on the hillside ahead of us. I was disappointed; I would have been happy with hours more cycling. But our cycle was to end at a small lodge in the jungle, at the end of an extremely steep trail. This was a final flourish which I enjoyed hugely, even though I set off far too enthusiastically and took my second fall of the day. I jumped back on and raced through the tree with my enthusiasm undimmed, and got to the end with bleeding elbows, a shoulder I could hardly move, and a huge grin on my face.
At the lodge, there were hot showers, and a huge amount of food. We had a fantastic couple of hours there, refuelling, and it was good to finally have a chance to talk to the people I'd cycled with: during the ride, everyone was pretty focussed on the road ahead. It was strange to find myself in hot jungle, when only hours before I'd been on a windswept pass high in the mountains.
And then it was time to head back to La Paz. This proved to be more frightening than the cycle down, because the weather had deteriorated and we had to negotiate the road in thick fog and heavy rain, as night was falling. We went much too fast for my liking, but we got back to the top unscathed. I was in an incredibly good mood. The guy from Manchester was right - this had been one of the most exciting things I'd done in South America.