Kilauea Iki sits immediately east of Kilauea's main summit caldera, a pit crater 244 meters deep, elongated roughly 3 kilometers by 1.5 kilometers on an east-west axis. It formed in the 15th century when part of the western flank of the Aila'au shield collapsed near its summit, partially draining the underlying magma chamber. A minor eruption in 1868, triggered by the great Ka'u earthquake -- a magnitude 7.9 event that caused extensive damage across Hawaii Island -- covered the crater floor in a thin layer of basalt. But this was a footnote. The eruption that would define Kilauea Iki was still a century away.

At 8:08 p.m. on November 14, 1959, the crater erupted. What followed was a month of extraordinary volcanic theater: 17 distinct eruptive episodes, each (except the last) beginning with lava fountaining and ending with lava draining back underground. The first episode lasted seven days. Most of the rest lasted less than 24 hours; the shortest, the 14th episode, was over in under two hours. Fountain heights started at 30 meters and climbed episode by episode, with the peak reaching 580 meters (1,900 feet) during Episode 15 -- the tallest lava fountains ever recorded in Hawaii at that time. By December 11, at the end of the 8th episode, the lava lake reached its greatest depth of 414 feet and a volume of 58 million cubic yards.

What made the 1959 eruption scientifically remarkable was not just its spectacle but its rhythm. Observers documented a two-way circulation of lava between the magma chamber and the surface -- the lake would fill during fountaining episodes, then drain partially back underground, only to refill in the next episode. Scientists recorded lava rapids, waves, and even a lava whirlpool within the crater. The drainback phenomenon provided volcanologists with rare data about how magma moves through a volcano's internal plumbing, and the eruption remains one of the most studied events in Hawaiian volcanic history.

The lava lake did not simply solidify and go quiet. Drilling projects in 1968 and 1988 tracked its cooling with scientific precision. The 1968 drill penetrated 30 meters of solidified crust before reaching molten rock at 60 meters, without ever hitting the bottom of the lake. The 1988 drill found molten material between 73 and 100 meters deep, revealing that the true lake depth was 135 meters -- greater than initially estimated, because the former crater floor had subsided into the underlying magma chamber under the weight of all that lava. The lake was still partially molten nearly three decades after the eruption ended.

Today, the Kilauea Iki Trail descends from the crater rim to the solidified lake floor and crosses it. Numbered markers correspond to a park guide that explains the geologic and botanical features along the way. Pressure ridges mark where the cooling rock contracted. Steam fumaroles hiss from cracks where rainwater meets residual heat below. Hardy 'ohi'a trees have begun colonizing fissures in the lava, their roots finding purchase in a landscape that was molten within living memory. The trail connects to the Crater Rim Trail and other paths through Hawaii Volcanoes National Park, making it one of the most unusual hikes in the world -- a walk across what was, not long ago, a lake of fire.