The beauty belies the volcano’s destruction. In 1991 alone, the eruption was blamed for the deaths of at least 250 people and for 10.1 billion Philippine pesos, or $245 million, in damage to crops, infrastructure and properties. The blast led to the permanent closure of Clark Air Base, a U.S. military installation, and devastated a 400-square-kilometer area. A typhoon that coincided with the eruption lent an apocalyptic feel to the events; rain-fed gushes of lahar inundated towns as red lightning streaked across the sky. Globally, the volcano’s output of ash and sulfur dioxide dragged temperatures down by 0.5 degrees Celsius (0.9 degrees Fahrenheit) for two years and, scientists say, hastened ozone depletion.

In a way, those doomsday details draw tourists today.

“I’m a fan of volcanoes. It’s my first opportunity to see the crater after the eruption,” said Wolfgang Buck, 49, a banker and hiking enthusiast from Germany. “It’s my first time to see such a beautiful caldera. I didn’t know there was so much water inside.”

From the viewing deck, a 170-step staircase descends to the white-sand beach. While too sulfuric for aquatic life, the lake’s cool, opaque waters are safe for swimming. Guides do warn that the lakebed drops off quickly and that the crater’s atmosphere is erratic, turning nippy at a mere drizzle.

“The thing is, we’re in a volcano, and that’s quite amazing. Years ago, it was just like any other mountain,” said Emmanuel Bernard, a 30-year-old accountant who was at the caldera with friends from France and Austria.

The lake, which is 2.5 kilometers in diameter, is around 85 meters deep, according to the Philippine Institute of Volcanology and Seismology. It had threatened to spill over the caldera’s rim until the institute undammed the waters in 2001 by digging a trench toward Zambales.

Pinatubo’s fire still manifests itself on the lake’s far shore. When guides shout “bangka,” the word for boat, boatmen who have been congregating in some open-air sheds respond. For 350 pesos, they will row tourists to the lake’s misty Pampanga side, where the water bubbles, and the sand is so hot that locals claim it will hard-boil eggs. The only other amenities are refreshments that some people carry to the crater in ice-filled polystyrene boxes to sell at a high markup.

Retracing the hike is fairly easy, although climbing from the shore back up the 170 steps can be exhausting. Visitors who have made arrangements in advance at the tourism office may be allowed to stay behind and camp in the crater.