Out on a barren plain in the western Philippines, men in military uniforms are packing up tents, exercises finished for the morning. Elsewhere, a boy in ragged T-shirts and flip-flops tugs at the rope tied round his buffalo’s neck, cajoling it into picking up the pace. But barring a few tufts of grass trying to heroically force their way through, the scene is a suffocating grey blanket of muddied ash.

Before 1991, this was a fertile valley where the people of Santa Juliana grew bananas. It’s now an eerie void that no one quite knows what to do with. Nothing is the same as it once was, and the beast that changed everything is the target for the convoy of 4x4s giddily bouncing along the rough terrain.

In the distance lies Mount Pinatubo, responsible for the second largest volcanic eruption of the 20th century. On June 15th, 1991, Pinatubo blew with such savage ferocity that the resulting ash cloud rose 35km into the air. Five cubic kilometres of material were thrown out, causing the summit to collapse and knocking 259 metres off Pinatubo’s height. The eruption was 10 times larger than that of Mount St Helens in the US 11 years earlier. And it was powerful enough to result, over the next two years, in global temperatures falling by half a degree Celsius.

The Earth had unleashed hell, and the skies decided to follow suit. With masochistic timing, Typhoon Yunya passed to the north of Pinatubo, sending a torrential deluge of rain as the ash flew up. The result was a legion of lahars – rivers of mud, ash and debris that slunk down the slopes of the volcano and into surrounding valleys. The unstoppable surges of concrete-consistency sludge flooded valleys at levels far beyond what the now-consumed rivers could have ever managed on their own.

To the west, rerouted rivers created a new lake – Mapanuepe – and homes were submerged forever beneath it. In the dry season, rooftops and church spires can be seen poking above the water line.

Many farmers have gamely battled on, switching to quick-maturing crops that can be harvested before the monsoons bring the lahars down the valleys again. But others have turned to tourism, realising that, while it destroyed so much, Pinatubo has created something truly incredible.

As the 4x4 ploughs on, the ground gets trickier to manoeuvre. Tyres continually have to dunk down into streams to access the easier path on the opposite side. Low-gradient silvery slopes become chunky grey walls. Hardy fringes of vegetation give way to pure, stark desolation.

Eventually, there is a point where it’s too steep for the vehicles to climb. From here, the only option is to go on foot towards the crater. It’s a steady uphill hike, suited to a plodding carthorse pace rather than a harelike race to the top, that takes around two hours. And that is two hours of feeling very small and insignificant indeed.

The initial stretches pass through several deathly pale cuttings, the walls more canyon than valley. What strikes home is the sense of impermanence. There’s no solidity or stability about anything in sight. Everything seems shell-shocked, liable to break down or fade away at the slightest provocation. The cliffs to either side are tall, but meek and quivering. Rocks frequently fall from them, sending up puffs of ash as they bounce down. It feels like the scenes in Inception where the carefully constructed dreamscape begins to fall apart. The walk is one through a surreal, crumbling world of impending collapse.

About 90 minutes into the hike, the gradient starts to get notably steeper. There’s a definite feeling of going up in each step. But more importantly, there are signs of life. The rubbly path begins to be flanked by green-topped hillocks. Tall grasses and plants attempt to brush against the thighs and midriff. Pinatubo is deep in the tropics and, for the first time, it begins to feel like that. As with many volcanoes, the surrounding land here will eventually become incredibly fertile.

The uphill plod continues until it unexpectedly reaches the top of a ridge. It’s the rim of the crater, and down in front is a sight so spellbindingly extraordinary that it will never leave the memory.

When Pinatubo’s summit was blown off and scattered far and wide, it left a gaping crater where it once was. Over the intervening years, that crater has filled with rainwater, creating a lake that has an almost lurid blue-green glow to it.

Surrounded by the jagged remnant shards of the one-time peak, the lake seems suspiciously otherworldly. It’s a mirage-like trap, designed to lure the tired and thirsty into its treacherous embrace.

Sure enough, signs on the edge advise against swimming in the lake. No one quite knows how deep it is, and no one knows what is beneath the water. It’s fair to say that there’s a fairly interesting mineral content – and the brightness is not matched by clarity.

This stops precisely zero walkers plunging in, however. There’s a steep drop-off – everyone’s out of their depth almost immediately. But despite not knowing where the water fits on the healing powers to bleach bath scale, it’s exceptionally refreshing. And the 360-degree view, of sharply rising crater walls and miniature powder-puff rock explosions, is something to treasure forever.

By the water’s edge is another unexpected sight. A slightly built local man with a floppy sun hat stands next to a pink and red wooden boat. Getting it up here shows an astonishing level of both logistical genius and entrepreneurial zeal, and it seems churlish not to reward that.

The drip-drying swimmers pile into the boat, gamely overlooking myriad potential health and safety issues, and the enterprising boatman heaves on the oars. Steam can be seen rising from a black sand mini-beach on the other side. It’s pointed out and the boatman shakes his head. “Too dangerous,” he says. It’s a jolting admission from someone who has a vested interest in it not being. Pinatubo has not yet gone back to sleep, and the lake lies on top of the vents that are releasing the pressure and preventing it from erupting again.

He deposits his human cargo slightly farther round on the shore. Toes dig into the sand and are swiftly retracted with aggrieved yelps. Below the surface layer, it is scorching hot. As reminders that you’re inside the crater of an active volcano go, this is a pretty effective one. In one way or another, life and landscape around Pinatubo will change soon. Until then, it is one of the most visually incredible places on earth.

In the area

The Bataan Peninsula

A dark World War II history makes the Bataan Peninsula worth the day trip. About 15,000 to 25,000 American and Filipino troops died after being marched along it following their surrender to Japanese forces in 1942. “Death March” markers are dotted along the main highway at one kilometre intervals. The 90 metre-tall Shrine of Valour on top of Mount Samat is a highlight, with battle scenes engraved around its base. A lift goes to the top for great views out over the mountains and Manila Bay. There’s also a museum on site. It’s around 81km down the highway from Clark.

Hundred Islands

Heading north-west instead, the Hundred Islands National Park features 123 limestone rock islands that have eroded to give them a mushroom-like appearance. It's a popular spot with Filipinos and snorkellers who float above beds of giant clams, but the clever way to explore is by hiring a kayak and paddling to an island that you can greedily keep to yourself. See www.hundredislands.ph.

The Cordillera

The north of Luzon Island is dominated by the Cordillera mountain range, which is speckled with cute cooler-climate towns and villages. The World Heritage-listed rice terraces around Banaue, which climb up mountain valleys like giant green steps, are the big ticket attraction. However, the caves full of mummified remains at Timbac, hiking trails and rafting trips on the Chico River are all hugely appealing in somewhat different ways. It’s the best part of a day’s drive to get to the Cordillera, so the wise allow time for a three- or four-day trip.

More information: www.itsmorefuninthephilippines.com

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