When we start taking our first steps on this trek, leaving behind Sembalun village, we have the distinct feeling that we have a challenging journey ahead. No mobile phones, no radios, no hot showers. At 3726 meters above sea level, Gunung Rinjani is Indonesia's second-highest volcano, and is located on Lombok Island. Balinese Hindus and Sasak Muslims consider Gunung Rinjani sacred and make pilgrimages to its peak and leave offerings to the gods. Hiking to its crater is a challenge for body and mind – three days walking an average of 12 hours a day is quite long enough to think and rethink about life and your values no matter what your religious beliefs.

Rinjani remains highly active and erupted as recently as May 2010, helping to form a new cone (Gunung Baru) inside Danau Segara Lake. It is risky and prohibited to explore the 41,330 hectares of the National Park by yourself if you are a foreigner. The only option is to hire a guide and at least two porters, paying around MOP1800 for a three-day package.

Once you take care of this formality, the main worry is to keep away – and sometimes run away - from aggressive monkeys who try to steal your food.

Our guide is Muksin, a 36-year-old high-school teacher who guides tourists up the grueling mountain path on his summer holidays to supplement the family's income. Wearing nothing on his feet but flip-flops, in the past 15 years, he has climbed up and down the mountain more than 200 times!

To reach the summit, there are two options: starting from Senaru and crossing the tropical jungle, or from Sembalun viewing the savannah fields. No matter where you start from, the narrow trail to reach the peak is the only one and the time it takes to get there is about the same. Walking from Sembalun village is less difficult during the first three hours. If you are a professional athlete or an experienced hiker, you may be able to reach Rinjani's crater within eight hours. But if you are not in a hurry to make it into the Guinness Book of Records, take your time and pace yourself.

Starting at six in the morning, it is possible to reach Pada Balong shelter, at an altitude of 1800m, for lunch. Here we grab a bowl of instant noodles with vegetables and boiled eggs, some cookies, hot tea and use the remaining half hour to lie down and stretch our muscles.

Up to this point, there's not much more to see than rice paddies, tobacco fields, cashew and mango trees, and banana palms. But you are very likely to meet other hikers coming back from a failed attempt at reaching the crater. Tony and Sammi came from England dreaming about Rinjani and are heading back without having touched its lava ash surface.

"Oh my God, it's impossible! It's disappointing to try so hard and not get there," Sammy complains with tears in her eyes. The couple was very close but gave up on the final stretch. "Our bodies failed," adds Tony, offering some advice.

"Go back. It will be less frustrating if you return at this point." Turning around is not an option for me. There is only one-way out: up! However, after 10 hours walking, Tony's advice is starting to echo in my ears. Higher up, at 2700m, and with my body asking for a full massage, I have a good reason to forget all my pains. Even the most well-travelled hikers will get emotional at the stunning views from the ridge of Pelawangan II. It is time to watch our first long sunset looking down at the 6km-wide cobalt-blue lake and then up to Rinjani's rim.

It is here, under a kind of natural planetarium, that we spend our first night. As the sun disappears, it gets cold, really cold – at least minus 8 degrees Celsius. We put on all our warm clothing, have supper – an Indonesian treat with prawn crackers, fried chicken rice, and eggs and try to count the stars and planets we can see in the clear sky. It's 7pm and time to be resting in preparation for the tougher part of the trek, the tight crater rim corridor.

The alarm clock rings. It's midnight. It was impossible to sleep even one hour due to the freezing cold. Tea, toast with butter and bananas in our stomachs may just be enough to keep us going for the next six-hours of climbing.

With a small flashlight, Muksin guides us into the darkness while the porters stay sleeping in the tent. Even our feet have become invisible in the dark.

"How far away are we from the summit?"

Muksin smiles at the repeated question and always gives the same answer: "Near," he lies. Actually, it is still five kilometers to the highest point of the rim. Once again, I remember Tony's advice about turning around sooner.

We are on the cliff face. It's too cold, too windy, and too painful, especially walking on all fours. We are practically frozen and don't even remember we have been trekking for six hours already. Then the rim suddenly appears. We made it and just in time for the sunrise! It's minus 14 degrees Celsius at the top. From here, it's possible to spot far archipelagos far below in the distance. We drink a naturally cold Coke to celebrate.

Staying for too long at the rim in such low temperatures would kill us. After 40 minutes relishing the view, it's time to go all the way down again. It should be easier going down than up except that we are walking down an almost 90-degree slope. My toes are begging for mercy but I have to forget about them. I just don't want to miss the view of the horizon, which was impossible to see in the darkness on the way up.

After four more hours we reach the campsite. The porters have prepared a rich breakfast to welcome us back, but deciding to share my banana pancakes with a cute gray monkey is a mistake. More than 200 follow him and the peace and quiet is over. I close my tent and watch my belongings – these are smart and experienced animals ready to get anything they find when we are not looking.

After half an hour of "playing with the kids", we pack again. The next leg of our journey is to climb down to the 'Child

of the Sea', Danau Segara Lake. It's a five-hour trek, and going down once more, with my toes screaming for a rest, I decide to abandon my trekking boots and do like the locals: save my feet with flip-flops.

When we get to the lake, the first thing we do is put on our swimwear and head directly to the natural hot springs that bubble up within the craters. Locals suffering from skin diseases trek here with medicinal herbs to bath and scrub. We do the same for our aching muscles and just relax.

Another sunset, another difficult evening. Due to the lake's high humidity, the temperature plummets and even the bonfire is not enough to keep us warm. Despite this, we try to rest and prepare for the next day's challenge: the final 12-hour trek home.

The last day offers the most astonishing views from the volcano itself and its lake. We cross through the middle of forests and savannahs, finishing with a long exploration through tropical jungle. Here you can see wild orchids, the long-tailed gray macaque monkey kera and, if you're lucky, the rare black ebony leaf monkey, known locally as 'lutung'. Rusa (deer) are forest dwellers that can be occasionally spotted along the trek trail and the smaller barking deer or 'kijang' has an alarm call with a distinct dog–like bark.

We finally see the National Park gate in Senaru village, but it's not time to celebrate yet. We still have to walk for one more hour before we get to civilization. And here finally we congratulate ourselves for earning the right to put our names in book of those who have also made it to the top Gunung Rinjani and down again!

How to get there from Bali: Public ferries travel between Padangbai (Bali) and Lembar (Lombok) every 90 minutes. The trip takes four hours and costs 32,000 rupiah per person (MOP30). There is a faster option costing 20 times more (690,000 rupiah/MOP635) reaching Lombok in two hours by the Blue Water Express (www.bwsbali.com). From other Indonesian islands, the best is to travel is by plane. From Jakarta, it takes around 90 minutes to reach Lombok's Selaparang Airport.

text and photos by Vanessa Amaro
translation by Boss Translation