There are fewer than 900 mountain gorillas on earth. To put that in perspective, critically endangered white rhino number 20,000; Bengal tigers 2,400.
So you can imagine how amazing it feels, after hacking and trekking through the jungle, to come face to face with a silverback and his band.
The gorillas live high in the mountains, and though threatened by poaching, habitat loss and human contagion, conservation efforts have brightened their outlook.
Here are two ways to do the trip of a lifetime.
There’s more to safari than the Big Five, says Nicola Brady, trekking in search of mountain gorillas and chimpanzees
"Don't move! Don't run!"
A young chimpanzee is barrelling through the forest, speeding along the undergrowth and smashing everything in his path. And he's heading straight for me.
Incredibly, considering my innate tendency towards wimpiness, I follow the guide's direction and stand still. If I run, he'll almost certainly chase me. As it is, the unfazed chimp charges past, grazing my thigh.
He draws to a halt at a towering fig tree, beating the trunk with his palms as he emits a resounding, guttural scream. It's a sound so primal, so powerful, that my eyes fill with inexplicable tears.
I'm in Kibale National Park, home to 13 species of primate and some 1,500 chimps - of which one community, the Kanyantare, are habituated. This means they are used to people like me, trekking in with cameras and a dumbstruck expression on their faces. But the chimps absolutely rule the roost in Kibale - the guides who lead tourists into the forest know them well, and also that their strength is equal to that of four adult men. "We're very lucky the chimps don't realise they're stronger than us," says Geofrey Tazenya, my guide. "The day they realise, we'll get a slap!"
There's a strong air of divilment to the chimps, too - we know it's time to leave when Toti, the new alpha of the gang, climbs to a tree above us and bestows our heads with a generous spray of urine.
It's about as close an encounter as you could ask for and, over a week spent in Uganda, I'm blessed with many more (none of which involve pee, thankfully). The country is positively teeming with the kind of wildlife you've been waiting your whole life to see. And because tourism isn't yet at the level of, say, Kenya, you're not battling with dozens of other Jeeps trying to get a good view.
At Murchison Falls, I cruise on the Nile and watch the hippos peek up from the water, as giraffes potter down between the elephants and crocodiles to take a drink, just feet from my boat. As I move south, the terrain becomes more mountainous, with steep, luscious slopes dappled in tea plantations and dense rainforest. This is Bwindi Impenetrable National Park, and I'm a bit anxious because, despite the name, I'm going in.
I'm decked out in full bushwhacking regalia - long sleeves, thick gloves, and increasing waves of altitude sickness that I'm keeping to myself. In front of me, armed guards forge through the unforgiving forest, hacking vines and branches with a machete as we weave to our final destination.
Bwindi is home to almost half of the 900 mountain gorillas left in the world, and just under half of them are habituated, ready for tourists who pay $600/€525 for the privilege of an hour with these enchanting creatures. Here's the kicker - you don't know how long your trek might take. You're all but guaranteed a sighting, thanks to the expert guides who lead the way, but you could be strolling for 20 minutes, or hiking for eight hours before you find your group.
I'm accompanied by a porter, who carries my backpack and helps me traverse the treacherous mountain. I had initially scoffed at the princessy notion of hiring a porter, but the oppressive heat, thick vines and razor-sharp thorns soon convince me otherwise. I start to resent all gorillas for living so damn far up what I'm now referring to as 'Bitch Mountain'.
And then I see him. We crouch on the floor as the gorilla eats, pulling leaves down towards his open mouth as he strips the branch clean and chomps away. We've been told to stay seven metres away from the gorillas, but Dwengye, a feisty teenager, strides over and pushes past me. Nyakiina, a 19-year-old, is reclining on her side near the silverback Bakwate. A young toddler gazes adoringly at her, and the guides whisper and point.
"Can you see the baby?"
Thinking they mean the adorable little fella at her side, I nod and smile. But then I spot a little pink ear, poking out of Nyakiina's arms. Just an hour before we arrived, Nyakiina gave birth. She's holding a tiny, wrinkled newborn, still covered in goo and nestled into her mother's chest. The sight is one so rare, the guides can't believe their eyes. Mothers usually hide away for at least a week following a birth - and they didn't even know she was pregnant.
But Nyakiina isn't like the others. She's confident, friendly and, right now, she's proud of her new baby. So proud, in fact, that she turns towards us, just for a second or two, and I could swear that she's showing us the baby, Rafiki-style.
Never in my wildest dreams could I have envisioned seeing such a sight. And boy, if it isn't worth every graze, scrape and strain. It's utterly magical.
How to do it:
Mahlatini Luxury Travel (mahlatini.com) offers an extensive 11-night holiday to Uganda from €10,400pp, including luxury lodge accommodation, chimp and gorilla tracking permits, all meals, flights and a private vehicle and guide. Other Uganda trips with Mahlatini start from €5,510pp.
What to pack
Anti-malarials and a Yellow Fever certificate are required. For gorilla tracking, wear long sleeves and light, long trousers. Thin gardener's gloves are a must, as well as solid, worn-in hiking boots. Bring a backpack too, for water and food, and wear a long lasting, high factor SPF.
It may be twice as expensive to see mountain gorillas in Rwanda, but the extra fee is absolutely worth it, says Sarah Siese.
It just got twice as hard to see mountain gorillas in Rwanda.
Financially, that is: this year, the price for an hour with these mighty apes doubled overnight from $750 to $1,500/€1,315. Yet paradoxically, paying them a visit has never been easier - gorilla numbers are slowly on the rise, and a new direct flight from London to Kigali has removed the hassle of hopping across Africa to reach the remote Virunga volcanoes.
Landing into Rwanda's capital, Kigali (the name means 'wide'), my first impression is of orderliness, cleanliness and a sort of provincial congeniality, where hibiscus hedges and yellow jacaranda decorate the roads, and poinsettia grow as large as trees. Bicycle and motorbike taxis (with standard-issue green helmets for all passengers) carry confident-looking city Sapeurs - who battle out catwalk dandyism in shiny suits and celebrated originality. Along the pavements, women size you up with penetrating stares, elegantly dressed in colourful Congolese kangas and ibitenge headdresses.
The road to Virunga is a solid blanket of greenery speckled with hamlets of single- storey adobe mud-walled homes. As roads become windier, terraces appear, along with muddy waterfalls and mile upon mile of bean crops. Finally, I reach my base at Virunga Eco Lodge (volcanoessafaris.com) - set at 2,300 metres, with 360-degree views overlooking the colossal volcanoes and twin lakes of Burera and Ruhonda.
Africa is always primal, exciting, earthy, and raw. And never more so than here, where the opportunity to sit among critically endangered mountain gorillas is, arguably, the continent's most exhilarating encounter. Pre-registered hikers meet just after dawn and are assigned one of the 10 habituated groups of mountain gorillas. The going is hard, gaitered and booted, with stick in hand. Hikers skirt along the perimeter of tracks scattered with pyroclastic boulders used as stepping stones to navigate mud that makes Glastonbury look like light work. A dense mist smudges the edges of a treeline that rises up, up, up to the grasslands leading to an impenetrable wall of mountain forest.
Only eight visitors are allowed per gorilla family per day to minimise intrusion, and all visitors are requested to keep seven metres away (a rule we keep, but they don't necessarily). Hikes vary in length and sightings are virtually guaranteed, but the effort requires physical fitness and agility. That said, while permits are cheaper in Uganda, foliage along the upper slopes of Volcanoes National Park in Rwanda has areas of open grassland and bamboos that aren't as dense, allowing better prospects for unobstructed views of families and the charismatic silverbacks.
Sitting up close with these lovable giants allows time to commune and scrutinise every aspect of their magnificence. Gorillas are intelligent. They have strong familial bonds; they laugh, grieve, make and use tools and, as we experience firsthand, have rich emotional relationships with their families. Despite weighing up to 200kg, they look invitingly cuddly, especially the five-month-old with his quizzical looks and crimpy Afro-frizz of a coat. It's no surprise that the animals share 98pc of our DNA; their digits, fingernails, brown eyes and perfect ears are all too familiar (even if the silverback's massive sloping forehead and flared, heart-shaped nostrils are not).
Nearly a quarter of a century after the Rwandan genocide, this country is back on its feet with burgeoning potential for nature tourism. Top-tier international hoteliers are opening lodges later this year but will find it difficult to beat Virunga Lodge for location. The best way to protect the world's mountain gorillas, I think, is through tourism. Gorilla permit fees support conservation, anti-poaching and research - I totted up the maths for Virunga, working out that they have a net revenue of €105,000 per hour. With 10pc of fees going directly to the local community, there's no comparable natural attraction in the world. Yes, it's expensive. But for me, this trip was priceless.
How to do it
RwandAir (rwandair.com) has flights from London Gatwick to Kigali from around €422 return. UK-based Cazenove + Loyd (cazloyd.com) offers a six-night adventure in Rwanda including one night in Kigali, two nights at Mount Gahinga lodge and three at Virunga lodge on a full-board basis, including two gorilla permits and two golden monkey trekking permits, return international flights and private transfers from £3,400/€3,855pp.