It was just after sunrise in the Simien Mountains, a collection of peaks in northern Ethiopia, when I heard rustling coming from a thicket of tall grass.
Seconds later, a troop of stocky, baboon-like primates called geladas came screeching out of the brush and weaved, like a school of fish, towards a nearby cliff.
I froze and watched the animals - males, females and babies - jump over the precipice at full tilt. It looked like mass suicide.
A few moments later, a rival group of geladas burst from the grass, howling and flashing incisors big enough to make a lion blush.
When tempers settled, I snuck towards the cliff's edge, expecting to see a collection of dead primates on the valley floor. Instead, the jumpers were calmly scrambling across a nearly sheer rock face, chatting - geladas have a 20-word vocabulary - and munching on tufts of grass jutting from the bluff.
It was just one of many cliff-side acrobatic routines I saw during a hike through the Simien Mountains, a rugged, untamed range that is fast becoming one of Africa's most popular trekking spots.
While the peaks are tucked away in a remote corner of Ethiopia, a reported 24,000 people visit every year, lured by stunning vistas and wildlife not found anywhere else on the planet.
One does not have to be a rugged outdoorsman to soak up the mountains, a Unesco World Heritage Site. Parts of the range are accessible on a long day trip from the nearby town of Gonder and there is the relatively plush Simien Lodge (www.simiens.com) inside the national park that surrounds the mountains. Another lodge is under construction.
But the best way to really experience the mountains is to put on your walking boots. So, in the waning days of Ethiopia's dry season, which lasts from October to May, I embarked on a four-day, three-night trip that would take me 22km from just inside the park gates to Chenek, a high-altitude campsite in the heart of the mountains.
It would also put me smack in the middle of a raging torrent.
It was my second day in the Simien Mountains when I reached the scenic Ginbar River, which courses through the mountains before plummeting 500m down the side of a cliff.
Normally not much more than a stream, earlierthan-expected rains had turned it into a waist-high series of rapids. There was no bridge and no way to bypass the river, said my guide, a spry 26-year-old named Gashaw Teshager. So he made a quick phone call and four men from a nearby village soon appeared.
"Here is our bridge," said Teshager.
The men nodded hello and waded into the river, pitching their bodies sideways to brace themselves against the current. Eventually, they planted themselves about an arm's length apart and the man closest to me reached out his hand and said with a laugh: "Go for swim today?"
I looked to Teshager. His eyes said: "It's this or we turn back." I stepped in and the current - just a few degrees above freezing - hit me like a jab from champion boxer Manny Pacquiao. My knees buckled, but the first man in line unabashedly grabbed my hips and pulled me towards him.
A few tentative steps later, I was in the fraternal embrace of another villager, then two more before finally planting my feet on solid ground.
"See, not so bad," Teshager yelled from the far bank.
The Ginbar is a product of the Simien's unique geography. Much of the range is a raised plateau that sits about 3,200m above sea level - or as high as parts of Tibet - with the tallest peaks reaching over 4,000m.
Scientists believe the mountains were formed about 30 million years ago by eruptions from a single massive volcano. Eons of wind and rain whittled away the soft volcanic rock, leaving behind jagged peaks, winding rivers and cliffs that plummet up to 1,500m straight down.
The forbidding landscape has made the Simien the final refuge of scores of rare animals, including the reclusive leopard; the Ethiopian wolf, the rarest canine in the world; the lammergeyer, a vulture-like scavenger; and the walia ibex, an endangered goat whose mountaineering skills put geladas to shame.
The park is also home to about 35,000 people, many of whom scrape a living by farming millet and raising cattle.
Teshager was one of them. Before tourism took off about 10 years ago, he was a shepherd living in a small cliffside village deep in the mountains. Getting to school was a 90-minute walk each way. Reaching the nearest city - about 40km away - was a two-day event.
"It wasn't easy growing up here," he said one night over dinner.
Development, though, rapidly changed the Simien. A road built in the late 1990s connected many villages to the outside world and led to an influx of tourist dollars, he said.
But that has also put more pressure on the Simien's fragile ecosystem. "Sometimes, I worry about the future," Teshager told me.
The next day, my third in the Simien, development was the furthest thing from my mind. After two days of travelling along dirt roads and ox paths, we pushed into the heart of the mountains, through low-lying clouds, around a stunning waterfall and onto Imet Gogo, a nearly 4,000m-high peak.
It was there that I could, for the first time, appreciate the massive scale of the Simien. From my viewpoint atop a narrow ridge, the earth looked shattered. Giant columns of rock, some hundreds of metres tall, shot up from the valley floor.
Mountains snaked across the horizon like ribbons on a wedding present. And, somewhere below me, geladas were howling.
Andrew Raven is a freelance writer and former copy editor with The Straits Times.
Churches carved four storeys underground
Ethiopia is more than just stunning landscapes. One of the oldest Christian countries in the world, it is home to an array of ancient religious sites.
Arguably the most famous are the rock-hewn churches of Lalibela, a Unesco World Heritage Site. Chiselled from solid volcanic rock about 900 years ago, the shrines plunge as much as four storeys into the earth. The churches are still used today and exploring them - through a warren of subterranean tunnels - is a once-in-a-lifetime experience.
A short flight away is Gonder, whose mediaeval castles, sprawling palaces and royal baths have earned it the moniker "Ethiopia's Camelot".
And in the remote north is Axum, an ancient capital and the beating heart of Ethiopian Christianity. The town is famous for its gargantuan stone stelae - some dating back 1,300 years - and a tiny nondescript chapel, which the Ethiopian Orthodox church says holds the biblical Ark of the Covenant.