In 1951, the newly formed Kansai Electric Power Company inherited an impossible problem. The Kansai region -- Osaka, Kyoto, Kobe, and their industrial surroundings -- was growing at a pace that outstripped the available electricity supply. Droughts compounded the crisis, forcing power rationing across western Japan. Post-war industry needed energy, and the rivers of the Northern Alps held enormous untapped hydroelectric potential. After years of geological and hydrological surveys, Kansai Electric announced in late 1955 that they would dam the Kurobe River deep in Toyama Prefecture's most rugged mountain terrain. The Kurobe Gorge was spectacular but brutal: steep granite walls, extreme seasonal flooding, and no road access. Everything -- concrete, steel, machinery, workers -- would have to be transported through tunnels bored under the mountains from the town of Omachi in Nagano Prefecture to the east.

Construction began in July 1956, and the Kanden Tunnel under Mount Akazawa became the project's first and most harrowing challenge. The fracture zone that stalled drilling for seven months nearly killed the project before concrete was ever poured. When crews finally broke through, they had built a lifeline that would carry supplies from Omachi to the construction site on the far side of the mountains. The first concrete for the dam was placed in September 1959. The structure that rose over the next four years was a variable-radius arch dam -- its curve designed to transfer the immense water pressure into the granite walls of the gorge on either side. By October 1960, the reservoir behind the dam had begun to fill. The spillway sits on the crest, with ten uncontrolled openings and three additional orifice pipes for controlled discharge. The human cost was staggering: 171 workers lost their lives over the seven years of construction, victims of rockfalls, tunnel collapses, and the unforgiving terrain of the gorge.

The purpose of all that sacrifice sits underground, carved into the mountain below the dam. Kurobe Power Station No. 4 houses four generators driven by Pelton turbines, producing a total installed capacity of 335 megawatts and an average annual output of one billion kilowatt-hours. The power station is an engineering cathedral buried in rock -- a vast chamber that channels water from the reservoir through penstocks and converts the massive hydraulic head created by the dam's 186-meter height into electricity for the Kansai grid. When it came online, Kurobe No. 4 represented a major step toward energy security for western Japan. The dam's crest elevation sits high above sea level in the alpine zone, and the reservoir stretches back through the gorge, its turquoise waters hemmed by peaks that rise another thousand meters above.

The scale and drama of Kurobe Dam made it irresistible to Japanese popular culture. The 1968 film The Sands of Kurobe, adapted from the novel The Sun of Kurobe, dramatized the construction and the toll it exacted in human life. The television series Project X dedicated episodes to the dam between 2000 and 2005. But it was the kaiju films that cemented Kurobe's place in the national imagination. In the 1961 film Mothra, the giant moth attacks the dam before its completion, causing it to break. Kurobe appears in 1964's Ghidorah, the Three-Headed Monster. In 1966's Gamera vs. Barugon, the giant turtle smashes through the hydroelectric plant and bursts the dam itself. Even the 2000 thriller Whiteout was filmed on location, with Kurobe renamed Okutowa Dam. That a concrete wall in a remote alpine gorge became one of the most frequently destroyed landmarks in Japanese cinema says something about the hold it has on the country's sense of monumental achievement.

Today, Kurobe Dam is the centerpiece of the Tateyama Kurobe Alpine Route, a spectacular mountain crossing that connects Toyama Prefecture to Omachi in Nagano using cable cars, ropeways, electric buses, and the Kanden Tunnel that nearly defeated the dam's builders. More than one million people visit the dam each year. The main attraction, from late June to mid-October, is the water discharge: up to fifteen tons per second blasting from the spillway gates, the mist catching sunlight to throw rainbows across the gorge. An observation deck on the dam's crest offers views of the turquoise reservoir stretching into the mountains and the sheer drop to the valley floor below. The monument to the 171 workers who died stands nearby, a reminder that the rainbow tourists photograph exists because men drilled through fracture zones and poured concrete in a gorge where the mountains tried to kill them at every turn.